Download Changes of State

Changes of State
Matter on earth can exist in any of three states- gas, liquid, or solid- and can change from one state to another.
Matter on earth can exist in any of three states- gas, liquid, or solid- and
three state とは gas, liquid, or solid のことです。
matter と metal を混同しないでください。
Matter on earth can change from one state to another.
Table 13-2 lists the possible changes of state.
In this section, you will examine these changes of state and the factors that govern them.
you will examine these changes of state.
examine: 詳しく調べる、精査する。
you will examine the factors
the factors govern them (= these change of state.)
TABLE 13-2 POSSIBLE CHANGES OF STATE
Change of State
Name
Example
solid → liquid
melting
ice → water
solid → gas
sublimation
dry ice → CO2 gas
liquid → solid
freezing
water → ice
liquid → gas
vaporization
liquid bromine → bromine vapor
gas → liquid
condensation
water vapor → water
あとで詳述されますが，liquid → gas でも boiling と vaporization は違います。
Equilibrium
In chemistry, equilibrium is a dynamic condition in which two opposing physical or chemical changes occur at equal
rates in the same closed system.
In chemistry, equilibrium is a dynamic condition.
equilibrium ってややこしいつづりですが、フランス語の aequi + libra (てんびん座のことを libra と
いいますよね) から来ているそうです。
In the equilibrium, two opposing physical or chemical changes occur at equal rates in the same closed system.
two opposing chemical changes: forward reaction/reverse reaction
二つの反応が「同じ速度」で起こるので，見かけ上「何も起こっていない」ように見えるのです。
「実際に何も起こっていない」わけではありません。
As an analogy, think of a busy department store at holiday time.
この analogy は「たとえ」
think of ～：～のことを考える
化学－分子は目に見えないですから、適当な「たとえ」を建てて想像することが大切です。その「たと
え」が正しいかどうか・・・ですけれども。
When the doors are first opened in the morning, customers begin to enter the store.
begin は後ろに動名詞・to-不定詞のいずれもとることができ，両者に意味の差はあまりない。
As time passes, some customers finish their shopping and leave the store, while new customers enter.
finish は動名詞のみをとります。動名詞は現在・過去、不定詞は未来のニュアンスを持っていますから，
「今やっていることを」終えるということなので動名詞が来ます。want to do, decide to do, try to do はす
べて「これからやること」なので to-不定詞です。そうすると、上の begin はどうなんだという気もし
ますが・・・
while：
「然るに」の意味で while を用いるのは口語的用法。書き言葉のときは whereas, although, though を
用いるのが普通。
At this point, the store is at a kind of equilibrium.
at this point：この時点で
a kind of ～：一種の～
The number of customers inside the store remains constant as long as new customers enter the store at the same rate that
other customers leave.
客に区別がつけられないなら，見た目は変わらないです。でも、もっと詳しく見て，客の一人一人が区
別できるのであれば、この前後で「変化」はおきています。
As closing time approaches, people leave the store at a faster rate than other people enter; equilibrium no longer exists.
店に５人の客がいて２人入ってきたと同時に４人出ていけば、店の中には３人しか客がいません。なの
で、前の状態とは明らかに違う状態が出現することになります。
たとえば、平衡にある状態で、１成分を増やすとそれを減らすように平衡がずれるという現象は、店の
前を通る人が増えると店の中のお客の数が増えて通りを歩いている人を減らすというように説明すれば、
上のたとえでも説明できそうな気がします (できますか？)。では、温度を変えると平衡が「ずれる」現
象は、この店の中のお客のたとえで説明できるでしょうか？
Equilibrium is a very important chemical concept.
Here you will learn about it in relation to changes of state.
この it は equilibrium.
in relation to ～：～に関連して
In Chapter 19, you will study equilibrium in terms of chemical reactions.
in terms of ～：～の点から
Equilibrium and changes of state
Consider the evaporation of a liquid in a closed container in which, initially, there is a vacuum over the liquid, as shown
in Figure 13-12.
Consider the evaporation of a liquid in a closed container
In the closed container, there is a vacuum over the liquid, as shown in Figure 13-12.
もちろん、真の「真空」は不可能ですので，ここでは「想像上の」コンテナを考えることになりま
す。
Assume that the contents of the container maintain the same temperature as the surroundings, which is normal room
temperature (approximately 22 ℃).
Assume that ～
the contents of the container maintain the same temperature as the surroundings.
The temperature of the surroundings is normal room temperature (approximately 22 ℃).
The liquid and the container are the system, that is, the sample of matter being studied.
system：系
that is,：つまり、言い換えると
「,」 があることに注意
Initially, there is a single phase inside this system - the liquid phase.
今は「想像上」です。蒸気の層がないと仮定しています。
A phase is any part of a system that has uniform composition and properties.
この any は「どこをとっても」ぐらいの意味かなあ
uniform：名詞なら「制服」ですが、この場合は形容詞なので「均一な」
数詞は厄介です。
uni - bi - tris：ラテン語系の接頭語。form はラテン語の forma (beauty) に由来するので uniform
mono - di - tri：ゲルマン語系の接頭語。pole はギリシャ語の polos (pivot) に由来するので monopole,
dipole
ただし、命名法のときは単純な記名の前にはdi/tri/tetra・・・複合基名の前には bis/tris/tetrakis/
Pd(PPh3)4: tetrakis(triphenylphosphine)palladium
A molecule at the upper surface of the liquid can overcome the attraction of neighboring molecules and evaporate if its
energy is high enough.
A molecule (at the upper surface of the liquid) can overcome the attraction (of neighboring molecules)
The molecule can evaporate
if energy (of the molecule) is high enough to evapolate.
.
Molecules that have entered the vapor phase behave as typical gas molecules.
Molecules [that have entered the vapor phase] behave as typical gas molecules
behave as ～：～らしく振舞う
Molecules have entered the vapor phase
この現在完了は「いったん入ってしまうと」くらいの気持ちか？
Some of these vapor molecules move down toward the liquid surface and condense, however, or reenter the liquid
phase.
however が文中にあるので変な文章ですが，この文章は「however」のうしろが「完全な文章」ではない
ので、文頭にもってくるべき「however」です
S V, however S’ V’ だと 「S’ V’ だけれども S V」なのですが、この場合はそうなっていません。
ですから、この文章は
However, some of these vapor molecules move down toward the liquid surface and condense, or reenter the
liquid phase.
なのです。でも、文頭に「However, 」がくると、ものすごく強い意志を表現することになるので，穏便
にいいたいときは、文中にさりげなく沈めるのだそうです。
この some は「いくらかの」ではなくて「こういう分子もある」くらいの意味ですね。
or reenter：この「or」は「あるいは」ではなくて「つまり」です
Condensation is the process by which a gas changes to a liquid.
Condensation is the process.
by the process, a gas changes to a liquid
As long as the temperature and surface area of the liquid remain constant, the rate at which its molecules enter the vapor
phase remains constant.
As long as the temperature
(of the liquid) remain constant
and surface area
as long as ～：～する間は、～する限りは
the rate remains constant.
the liquid’s molecules enter the vapor phase at the rate
The rate at which molecules pass from the vapor phase to the liquid phase also depends upon the concentration of
molecules in the vapor phase, however.
この文末の however も、本来は文頭に来て、前の文章をうけます ([前の文章] だけど)。
The rate (at which molecules pass from the vapor phase to the liquid phase) also depends upon the concentration
(of molecules in the vapor phase).
depend on (upon) ～：～に依存する
分子がどの相からどの相へ移動しているのか、間違えないこと。
Concentration is the number of particles per unit volume.
unit volume：単位体積。ただし、それが 1 cm3 なのか 1 L なのか、はたまた 1 m3 なのかは、話の内
容で決まってきます。
per unit volume：単位堆積あたりの
Initially, this concentration and therefore, the rate of condensation are zero, as shown in Figure 13-12a.
this concentration
are zero
the rate of condensation
定義として、最初は「液体の上部には真空がある」となっていますので、気体分子は存在しませんから、
その濃度も 0。気体の分子が液体になる速度は気体の分子の濃度に依存しますので，これまた 0 です。
何の concentration であり、何の rate なのか、前後の文脈からきちんと取れるようになりましょう。
as shown in ～：～に示すように
As time passes and evaporation continues, the concentration of molecules in the vapor phase increases.
As A, B：A するにつれて B となる
This increase in concentration results in an increase in the rate at which molecules reenter the liquid phase, as shown in
Figure 13-12b.
increase を動詞ととらないこと。increase in ～：～の増加
この文の動詞は result in (という結果になる) です。
at which 以降は the rate の説明です。
Eventually, the rate at which molecules condense equals the rate at which molecules evaporate, as shown in Figure
13-12c.
the rate (at which molecules condense) equals the rate (at which molecules evaporate)
at which はそれぞれ直前の the rate を修飾します。
In other words, equilibrium has been reached.
In other words：言い換えると
現在完了形になっているので「この時点で」の意味がこめられています。
Whenever a liquid changes to a vapor, as it does when it evaporates, it absorbs heat energy from its surroundings.
でてくる it はすべて liquid を指しています。
意味的には
Whenever a liquid changes to a vapor, as it does when it evaporates
it absorbs heat energy from its surroundings.
の二つの部分に分けて訳をとります。
Evaporation can therefore be represented as
liquid + heat energy → vapor
Whenever a vapor condenses, it gives off heat energy to its surroundings.
give off：放出する、放つ
Condensation can therefore be represented as
vapor → liquid + heat energy
The liquid-vapor equilibrium can be represented as
liquid + heat energy →← vapor
The "double-yields" sign in the equation above represents a reaction at equilibrium.
"double-yields" sign というのは両矢印のことでしょうね、そういうのかどうかは知りませんが。
動詞は represents
reaction at equilibrium は「反応が平衡状態にある」ということ
This means that the reaction can be read in either direction.
this は a reaction at equilibrium
read は原形ではありません。read の過去分詞形です
in either direction：どちらの方向にも
The forward reaction is represented when the equation is read from left to right:
liquid + heat energy → vapor.
the equation is read from left to right：式を左から右の方向へ読む
The reverse reaction is represented when the equation is read from right to left:
vapor → liquid + heat energy.
Le Chatelier's principle
ル・シャトリエの原理。フランス人の名前は読みにくいですねえ
In 1888, the French chemist Henri Louis Le Chatelier (1850-1936) developed an important principle that enables
scientists to predict how a change in the conditions of a system at equilibrium will affect the equilibrium.
In 1888, the French chemist Henri Louis Le Chatelier (1850-1936) developed an important principle.
the principle enables scientists to predict it
how will a change (in the conditions of a system) (at equilibrium) affect the equilibrium.
affect = have an effect on
Le Chatelier's principle can be stated as follows:
If any of the factors determining an equilibrium are changed, the system will adjust itself in a way that tends to
minimize that change.
any (of the factors) (determining an equilibrium) are changed
the system will adjust itself in a way
the way tends to minimize that change.
This principle applies to all kinds of equilibria, both physical and chemical.
datum - data,
Le Chatelier's principle can be used to predict how the liquid-vapor equilibrium in the system just discussed changes
when the temperature of the system is increased from 20 ºC to 50 ºC.
Le Chatelier's principle can be used to predict it.
how does the liquid-vapor equilibrium (in the system) (just discussed) change?
the temperature of the system is increased from 20 ºC to 50 ºC.
The equilibrium of the system can be represented as
liquid + heat energy →← vapor
According to Le Chatelier's principle, the system will adjust itself to counteract an increase in temperature.
according to～：～によると
○○の報告によると、などという場合にも用いる。
20 ºC → 50 ºC
In this case, the forward reaction is endothermic - it absorbs energy.
endo (内) - exo (外)
This reaction will be favored in order to counteract the rise in temperature.
endothermic な反応が起こると、系からエネルギーが吸収されるので、系の温度がさがります。これが、
系の温度を「上げる」ことと「反対の作用」をします。
The forward reaction temporarily proceeds at a faster rate than the reverse reaction, until finally a new equilibrium is
reached.
temporarily - finally
At this new, higher-temperature equilibrium, the concentration of vapor is higher than it was at the lower-temperature
equilibrium.
the concentration of vapor is higher than the concentration* of vapor was at the lower-temperature equilibrium.
the concentration* は低温のときの濃度なので，was となっています。
That is, the equilibrium system has shifted to the right, favoring the products.
that is, これは「それは」ではなくて、「すなわち」です。カンマの有る無しに注意してください。
平衡が右にずれれば、生成物が多くできますね？
At the new equilibrium point, the reverse reaction, condensation, occurs at a faster rate than it did at the old equilibrium
point so that the rates of the reverse and forward reaction are equal.
長い文章ですから、バラバラにしていきましょう。
At the new equilibrium point
the reverse reaction, condensation, occurs at a faster rate than it did at the old equilibrium point
forward reaction が vaporization, その reverse reaction は condensation reaction。the reverse reaction と
condensation は等価です。
equilibrium point では forward reaction rate と reverse reaction rate は等しくなります。
forward reaction が以前の (低温のときの) 速度より速くなっているわけですから、新しい平衡状態
では reverse reaction も以前の (低温のときの) 速度より速くなります。
so that the rates of the reverse and forward reaction are equal.
Suppose, on the other hand, that the temperature of the system in equilibrium at 20 ºC is lowered to 5 ºC.
on the other hand：その一方で。これまでは温度を上げることを考えてきましたが，今度は下げてみまし
ょうということです。
According to Le Chatelier's principle, the system will adjust itself to counteract the decrease in temperature.
Here the reverse reaction will be favored because it is exothermic and releases energy.
系の温度が下がるときは、それを「打ち消す」には熱を出す反応がおこるとよいのです。
Equilibrium is shifted to the left and reestablished at 5 ºC with a vapor concentration less than that at 20 ºC.
逆反応：蒸気が液体に戻る反応
が起きるので，蒸気の濃度は下がってしまうのです。
Suppose the mass in the system and the temperature of this equilibrium system remain the same, but the volume of the
system suddenly increases.
この suppose は文章全体にかかります。
mass, temp: remain
volume
: increase
What happens to the equilibrium?
Initially, the concentration of molecules in the vapor phase decreases because the same number of vapor-phase
molecules now occupy a larger volume.
concentration = number/volume ですから。
Because the concentration of vapor molecules decreases, fewer vapor molecules strike the liquid surface and return to
the liquid phase at any given time.
下のようなマンガを考えてみると、一番下の層にある分子が液体になると仮定すると，左側 (60 分子/10
層) では最下層には 6 個、右側 (60 分子/12 層) では５個分子がある。つまり、対象となる分子が 6 →
5 に「減って」いることが分かる。
The rate of condensation therefore decreases.
The rate of evaporation, which remains the same as it was before, is now higher than the rate of condensation.
温度が一定ですからねえ、出て行くほうの速度は変わらないのです。
As a result, an additional net evaporation of liquid counteracts the imposed decrease in vapor concentration by
increasing the number of vapor molecules.
液相から気相に６個出てきて「同時に」気相から液層に６個入っていったら、気相の分子の数は変わら
ないんですけれど、気相から液層に５個しか入っていかなかったら 6－5＝1 個、気相の分子が増えてし
まいます。
When equilibrium is reestablished, the concentration of molecules in the vapor phase is the same as in the system of
smaller volume.
最下層の分子の数が6個になるまで蒸発は続きます。気体分子は激しく運動しているから，すべての層で
含まれる分子の数は同じですから、結局、すべての層が6個ずつの分子を含むまで蒸発が続きます。そう
すると，膨張させる前と同じ状況が起こることになるのです。注目するのは，その相に含まれる「分子
の数」ではなくて，「分子の濃度」です。
Because there was a net movement of molecules from the liquid phase to the vapor phase, the number of molecules in
the liquid phase has decreased.
上の絵でいうと，液相から気層へ12個の分子が移動しています。
The equilibrium has therefore shifted to the right.
液体の分子の数が減って気体の分子の数が増えているのですから、反応は左から右に起こっています。
なので、平衡も右にシフトしているのです。
SECTION OBJECTIVES
Explain the relationship between equilibrium and changes of state.
Predict changes in equilibrium using Le Chatelier's Principle.
Explain what is meant by equilibrium vapor pressure.
Describe the processes of boiling, freezing, melting, and sublimation.
Interpret phase diagrams.
Figure 13-12.
A liquid-vapor equilibrium developing in a closed system,
(a) At first there is only liquid present but molecules begin to evaporate.
(b) Evaporation continues at the same rate.
There is a relatively low concentration of vapor.
Vapor molecules are condensing to liquid, however.
The rate of condensation is lower than the rate of evaporation,
(c) The concentration of vapor has increased to the point at which the rates of evaporation and condensation have
become equal.
The concentration of vapor has increased to the point
at the point, the rates of evaporation and condensation have become equal.
この時点になって「初めて」等しくなるので，現在完了形が使われる。
Equilibrium has been reached.
The amounts of liquid and of vapor now remain constant.
Equilibrium Vapor Pressure of a Liquid
The vapor molecules in equilibrium with a liquid in a closed system exert a pressure proportional to the vapor
concentration.
The vapor molecules (in equilibrium) (with a liquid) (in a closed system) exert a pressure
the pressure is proportional to the vapor concentration.
is proportional to ～：～に比例する。
The pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature is called the
equilibrium vapor pressure of the liquid.
動詞は is called。be 動詞は分かりやすいです。だから、それより前はすべて S。中心は the pressure
The pressure is called the equilibrium vapor pressure of the liquid.
equilibrium vapor pressure：平衡蒸気圧
The pressure is exerted (by a vapor) (in equilibrium) (with its corresponding liquid) (at a given temperature)
４つのカッコがどう絡んでいるかですね
Solids can also have an equilibrium vapor pressure, since some of the solid can change directly to vapor.
簡単な単語なのですが，since のとり方には注意してください。
A, since B. Since B, A. 「B なので A」です。「A だから B」ではありません (論理が逆転します)。
Figure 13-13 shows the apparatus used to measure the equilibrium vapor pressure of a solid and of a liquid at a variety
of temperatures.
Figure 13-13 shows the apparatus.
apparatus 複数形は apparatuses
The apparatus is used to measure the equilibrium vapor pressure of a solid and (the equilibrium vapor pressure) of
a liquid at a variety of temperatures.
When the equilibrium vapor pressure of water is graphed, as in Figure 13-14, the result is a vapor
pressure-vs.-temperature curve for liquid water.
the equilibrium vapor pressure of water is graphed, as in Figure 13-14.
the result is a vapor pressure-vs.-temperature curve for liquid water.
Liquid water can exist in equilibrium with water vapor only up to a temperature of 374.1ºC.
up to：低温側から徐々に温度を上げていって，「この温度まで」というイメージです。
ちなみに，水の臨界点は 374 ºC、218気圧です。
As discussed later in this chapter, neither liquid water nor solid water can exist at temperatures above 374.1ºC.
neither A nor B
The curve in Figure 13-14 shows that the equilibrium vapor pressure of water increases as temperature increases,
although not by direct proportion.
The curve in Figure 13-14 shows ～
the equilibrium vapor pressure of water increases as temperature increases, although not by direct proportion.
A as B：B するにつれて A
direct proportion：正比例
although のとり方に注意。
This finding is consistent with Le Chatelier's principle since the concentration of water vapor, and therefore the
equilibrium vapor pressure of water, increases in response to temperature increases.
This finding is consistent with Le Chatelier's principle
is consistent with ～：～と一致している。整合性が取れている
the concentration of water vapor
increases in response to temperature increases
the equilibrium vapor pressure of water
in response to ～：～に応じて
At any given temperature, water vapor exerts a specific vapor pressure.
specific：その温度に特定の (値)
Figure 13-13 This apparatus can be used to measure the equilibrium vapor pressure of a liquid or a solid.
The increase in equilibrium vapor pressure with increasing temperature can be explained in terms of the particle models
for the liquid and gaseous states.
ここから先，やたらと increase が出てきます。名詞？動詞？間違えないこと。
動詞は can be explained
in terms of ～：～によって，～の観点から
Increasing the temperature of a liquid increases its average kinetic energy, which in turn increases the number of its
molecules that have enough energy to escape from the liquid phase into the vapor phase.
Increasing the temperature of a liquid increases its average kinetic energy
increases its average kinetic energy in turn increases the number of its molecules
the molecules have enough energy to escape from the liquid phase into the vapor phase.
下線部が動詞
in turn：次に、順順に、
enough － to ～：～するのに十分な－
This increased evaporation rate increases the concentration of molecules in the vapor phase, thus disturbing the
liquid-vapor equilibrium.
This increased evaporation rate increases the concentration of molecules in the vapor phase
「この増加した蒸発速度が」でもいいかもしれないけれど、「蒸発速度が増加すると」くらいかな
(As the result), This increased evaporation rate disturbs the liquid-vapor equilibrium.
But the increased concentration of molecules in the vapor phase then increases the rate at which molecules reenter the
liquid phase.
the increased concentration (of molecules) (in the vapor phase) (then) increases the rate
molecules reenter the liquid phase at the rate.
Soon equilibrium is reestablished, but at a higher equilibrium vapor pressure.
Every liquid has a specific equilibrium vapor pressure at a given temperature.
This is because all liquids have characteristic forces of attraction between their particles.
Lesson 8 の LD では attractive forces between particles という表現が出てきます。
The stronger these attractive forces are, the smaller is the percentage of liquid particles that can escape to the vapor
phase at any given temperature, and therefore, the lower is the equilibrium vapor pressure.
The stronger these attractive forces are, the smaller the percentage of liquid particles is
The (比較級), the (比較級) の構文。
後半は後ろに that 節がつながるので、動詞が先に出る。
the liquid particles can escape to the vapor phase at any given temperature
the smaller the percentage of liquid particles is, the lower the equilibrium vapor pressure is.
The (比較級), the (比較級) の構文。
Volatile liquids, which evaporate readily, have relatively weak forces between their particles.
Volatility：揮発性
Volatile liquids have relatively weak forces between their particles
Volatile liquids evaporate readily
Ether is a typical volatile liquid.
Nonvolatile liquids, which evaporate slowly, have relatively strong attractive forces between particles.
Molten ionic compounds are examples of nonvolatile liquids.
molten salt: 熔融塩
Be careful not to confuse the equilibrium vapor pressure of a liquid with the pressure of a vapor that is not in
equilibrium with its corresponding liquid.
Be careful not to do: しないように気をつけなさい。
confuse A with B：A と B とを混同する。
The equilibrium vapor pressure of a liquid depends only on temperature.
depend on ～：～に依存する
The pressure of a vapor that is not in equilibrium with the corresponding liquid obeys the gas laws, like any other gas,
and is inversely proportional to its volume at constant temperature, according to Boyle's law.
The pressure of a vapor obeys the gas laws, like any other gas,
the vapor is not in equilibrium with the corresponding liquid
液体と平衡にある蒸気は、蒸発－凝縮平衡によって、圧力が変わると平衡の位置がずれてしまい、
こういう議論ができなくなります。ここでいう「not in equilibrium」は「平衡状態に達していない」
のではなく、「平衡状態ではない－液体がなくて平衡も何もない」状態です。
The pressure of a vapor is inversely proportional to its volume at constant temperature, according to Boyle's law.
inversely proportional：反比例。Boyle の法則は「pV = 一定」でしょ？
according to ～：～によると
Figure 13-14 This graph shows the vapor pressure curve for water.
Boiling
Equilibrium vapor pressures can be used to explain the common phenomenon of boiling.
－ be used to ～：～するために－を用いる。－を用いて～できる。
能動文だと意味が全く違ってくる。I used to ～：以前はよく～したものだった。
phenomenon：複数形は phenomena
Boiling is the conversion of a liquid to a vapor, within the liquid as well as at its surface when the equilibrium vapor
pressure of the liquid is equal to the atmospheric pressure.
Boiling is the conversion of a liquid to a vapor, within the liquid as well as at its surface
within the liquid as well as at its surface は boiling の起こる場所を述べています。
conversion of A to B：A の B への変化 (転換)
the equilibrium vapor pressure of the liquid is equal to the atmospheric pressure.
is equal to ～：～に等しい
沸騰と蒸発の違いに注意してください。
A liquid does not boil if its equilibrium vapor pressure is lower than the atmospheric pressure.
でも、この状況でも、液体から気体への「蒸発」は起こっています
As the temperature of the liquid is increased, the equilibrium vapor pressure also increases.
Finally, a temperature is reached at which the equilibrium vapor pressure is equal to the atmospheric pressure.
a temperature is reached at the temperature
the equilibrium vapor pressure is equal to the atmospheric pressure at the temperature.
This temperature is known as the boiling point.
boiling point は資料集などではよく B. p. と省略 (abbreviate) されます。
The boiling point of a liquid is the temperature at which the equilibrium vapor pressure of the liquid is equal to the
atmospheric pressure.
The boiling point of a liquid is the temperature
at the temperature, the equilibrium vapor pressure of the liquid is equal to the atmospheric pressure.
沸点の定義です。
The lower the atmospheric pressure is, the lower is the boiling point; the higher the atmospheric pressure is, the higher
is the boiling point.
富士山の頂上でご飯を炊くと芯が残る理由ですね。減圧蒸留の原理でもあります。
This is the reason why foods take longer to cook at high elevations where atmospheric pressures are lower than at sea
level.
elevation：海抜
This is the reason why ～：これが～であることの理由です。
take long：時間がかかる。
This principle is the basis for the operation of the pressure cooker shown in Figure 13-15.
pressure cooker：圧力鍋
operation：操作
The pressure cooker increases the boiling temperature of the water inside by allowing a certain amount of steam
pressure to build up over the surface of the boiling water.
allow A to do：A に do させる
build up：(徐々に) 増加する。
over the surface of the boiling water：沸騰している水の表面にわたって
水にかかる圧力が上がると、水の沸点が高くなり，120 ºC の「液体の水」というものもできる。そうす
ると、それまでは「100 ºC でしか煮炊きできなかったのが、120 ºC でも調理できる」ことになる。
In contrast, a device called a vacuum evaporator brings about boiling at lower-than-normal temperatures.
lower-than-normal：通常よりは低い
brings about：引き起こす
boiling：動名詞。沸騰
Vacuum evaporators are used to remove water from milk and sugar solutions.
粉ミルクとか粉砂糖を作っているのでしょう。
Under reduced pressure, the water boils away at a temperature low enough to avoid scorching the milk or sugar.
boil away：沸騰しつづける
砂糖の溶液を煮詰めると、すぐカラメルみたいになってしまうんですよねえ。
This process is used to prepare evaporated milk and sweetened condensed milk.
At normal atmospheric pressure (760 mmHg, or 101.3 kPa [0.1 Mpa]), the boiling point of water is exactly 100 ºC.
これは定義ですから，「exactly」に 100 ºC なのです。
This temperature is known as the normal boiling point of water.
is known as ～：～として知られている
It takes longer to hard-boil an egg in Denver, Colorado, than it does in Boston, Massachusetts, however, because water
boils at a lower temperature in Denver.
Denver：アメリカ合衆国、コロラド州の州都。ロッキー山脈の東麓、海抜1610メートルに位置する高原
都市。
Boston：アメリカ合衆国、マサチューセッツ州の州都。大西洋に面する港湾都市。
Denver, Colorado は「Denver と Colorado」ではなくて「Colorado の Denver」です。
hard-boil an egg：卵をかたく煮る
Food cooks faster in a pressure cooker because water boils at a higher temperature.
Food cooks faster (in a pressure cooker) (than in a normal pan) because water boils at a higher temperature.
The normal boiling points of water and some other liquids are shown in the graph in Figure 13-16.
Note that the normal boiling point of each liquid is the temperature at which the liquid's equilibrium vapor pressure
equals 760 mm Hg.
Note that ～：～に注意しなさい
the normal boiling point (of each liquid) is the temperature
at the temperature, the liquid's equilibrium vapor pressure equals 760 mm Hg.
equal には「～と等しい」という他動詞もあります。
is equal to
equals ～ (to はいらない)
If you were to measure carefully the temperature of a boiling liquid and its vapor, you would find that both are at the
same constant temperature.
「実際には測定したわけではないのだけど、もし測定したら・・・ということが分かるでしょう」とい
うことで仮定法です。
相変化の場合は、与えた熱はすべて相変化に使われる (潜熱：latent heat) ので、溶液の温度も蒸気の温
度も変化しません。
As you know from experience, heat must be continuously added in order to keep a liquid boiling.
experience：経験，experiment：実験。混同しないこと。
in order to ～：～するために
keep doing：keep to do は誤り
A pot of boiling water stops boiling almost immediately after it is removed from the stove.
Since the temperature and, therefore, the average kinetic energy of the particles in a system at the boiling point remain
constant despite the continuous addition of heat, where does the added heat energy go?
the temperature and the average kinetic energy (of the particles) (in a system) (at the boiling point) remain
constant despite the continuous addition of heat
この動詞は remain：remain constant - 一定値を保つ
despite = in spite of (にもかかわらず)：でも、despite は of を伴わない (despite of は誤り)
分子運動論から、気体分子の平均運動エネルギー <K.E.> は <K.E.> = (3/2)RT (R は気体定数、T は
気体の温度) です。
where does the added heat energy go?
It is used to overcome the attractive forces between liquid molecules during the liquid-to-gas change, and is stored in
the vapor as potential energy.
the added heat energy is used to overcome the attractive forces (between liquid molecules) (during the
liquid-to-gas change)
the added heat energy is stored in the vapor as potential energy.
The amount of heat energy required to vaporize one mole of liquid at its boiling point is known as the liquid's molar
heat of vaporization.
The amount of heat energy which is required to vaporize one mole of liquid at its boiling point is known as the
liquid's molar heat of vaporization.
The amount of heat energy is known as the liquid's molar heat of vaporization.
heat of boiling ではないことに注意しましょう。
heat energy is required to vaporize one mole of liquid at its boiling point
The magnitude of the molar heat of vaporization is a measure of the attraction between the particles of the liquid.
magnitude：大きさ
measure：尺度
The stronger this attraction is, the more energy is required to overcome it, and, therefore, the higher is the molar heat of
vaporization.
The stronger this attraction is, the more energy is required to overcome this attraction,
the more energy is required to overcome this attraction, the higher is the molar heat of vaporization.
Each liquid has a characteristic molar heat of vaporization.
Compared to other liquids, water has an unusually high molar heat of vaporization.
When water is compared to other liquids, water has an unusually high molar heat of vaporization.
compare to ～：～と比較する
This property, which you will learn more about in the next section, makes water a very effective cooling agent.
make A B：A を B にする
make A do：Ａ に do させる
When water evaporates from your skin, the escaping molecules carry a great deal of heat away with them.
the escaping molecules：あなたの皮膚から逃げていく分子→水蒸気のこと
carry away：運び去る
a great deal of：かなりの
Figure 13-15.
A pressure cooker makes use of elevated pressure to raise boiling point and shorten cooking time.
A pressure cooker makes use of elevated pressure to raise boiling point
to shorten cooking time
make use of = use
Figure 13-16. The normal boiling point of each of these liquids is the temperature at which the liquid's equilibrium
vapor pressure equals 760 mm Hg (shown here as a dotted line).
The normal boiling point of each of these liquids is the temperature
at the temperature, the liquid's equilibrium vapor pressure equals 760 mm Hg (shown here as a dotted line).
Freezing and Melting
The physical change of a liquid to a solid is called freezing.
A is called B：A は B と呼ばれる。A のことを B という。
Freezing involves a loss of energy, in the form of heat, by the liquid:
liquid → solid + heat energy
in the form of ～：～の形で
In the case of a pure substance, this change occurs at constant temperature.
in the case of ～：～の場合は
The normal freezing point is the temperature at which the solid and liquid are in equlibrium at 1 atm (101.3 kPa)
pressure.
The normal freezing point is the temperature
at the temperature, the solid and liquid are in equilibrium at 1 atm (101.3 kPa) pressure.
This observation indicates that the particles of the liquid and the solid have the same average kinetic energy.
This observation indicates that ～
the particles of the liquid and the solid have the same average kinetic energy.
Therefore, the energy loss during freezing is a loss of potential energy that was present in the liquid.
この therefore は前の文全体を受けます
the energy loss (during freezing) is a loss of potential energy
loss は「損失」、lose は「うしなう」、lost は「失った」、loose は「解き放つ」
the potential energy was present in the liquid.
At the same time as energy decreases, there is a significant increase in order, since the solid state of a substance is much
more ordered than the liquid state, even at the same temperature.
At the same time as energy decreases：At the same time as ～：～すると同時に
there is a significant increase in order：increase in ～：～の増大、～が大きくなる
the solid state of a substance is much more ordered than the liquid state, even at the same temperature.
The reverse physical change, melting, also occurs at constant temperature.
reverse：逆の
The reverse physical change「すなわち」melting：これら二つは同格
Melting is the physical change of a solid to a liquid.
The melting point is the temperature at which the transition from the solid phase to the liquid phase occurs.
The melting point is the temperature
at the temperature, the transition (from the solid phase to the liquid phase) occurs.
from A to B：A から B への
During melting, the melting solid continuously absorbs heat:
solid + heat energy → liquid
The amount of heat energy required to melt one mole of solid at its melting point is its molar heat of fusion.
The amount of heat energy which is required to melt one mole of solid at its melting point is its molar heat of
fusion.
The amount of heat energy is its molar heat of fusion.
heat of melting とは言っていないことに注意しましょう
the heat energy is required to melt one mole of solid at its melting point
The heat absorbed by the melting solid increases the potential energy of the solid as its particles are pulled apart in
opposition to the attractive forces tending to hold them together.
The heat which is absorbed by the melting solid increases the potential energy of the solid as the solid particles are
pulled apart in opposition to the attractive forces which is tending to hold the solid particles together.
The heat increases the potential energy of the solid
The heat is absorbed by the melting solid
the solid particles are pulled apart in opposition to the attractive forces
pull apart：バラバラにする
in opposition to ～：～に対抗して
the attractive forces are tending to hold the solid particles together.
At the same time, there is a significant decrease in order.
For pure, crystalline solids, the melting point and the freezing point are the same.
For
pure
the melting point
solids,
crystalline
are the same.
and the freezing point
At equilibrium at the melting or freezing point, melting and freezing proceed at equal rates according to the following
general equilibrium equation:
At equilibrium at the melting or freezing point
melting and freezing proceed at equal rates
平衡なのですから、両向きの反応が同じ速度で起こるのです。
according to the following general equilibrium equation:
according to ～：～に従って
solid + heat energy →← liquid
At normal atmospheric pressure, the temperature of a system containing ice and liquid water will remain at 0 ºC as long
as both ice and water are present, no matter what the surrounding temperature.
At normal atmospheric pressure
融点は圧力に依存しますから・・・
the temperature of a system (which is containing ice and liquid water) will remain at 0 ºC
as long as both ice and water are present, no matter what the surrounding temperature.
as long as ～：～である限り
no matter what ～：どんな～であっても
夏のどんな暑い日でも、氷の入った飲み物は 0 ºC なのです。
As predicted by Le Chatelier's principle, adding heat to such a system shifts the equilibrium to the right, increasing the
proportion of liquid water and decreasing that of ice.
As predicted by Le Chatelier's principle
As predicted by ～：～から予測されるように
adding heat to such a system shifts the equilibrium to the right
平衡が右にずれる、ということは・・・
adding heat to such a system increases the proportion of liquid water
decreases the proportion of ice.
ということなのです
Only after all the ice has melted will the addition of heat increase the temperature of the system.
倒置されているので，元に戻すと
Only after all the ice has melted, the addition of heat will increase the temperature of the system.
Under sufficiently low temperature and pressure conditions, a liquid cannot exist.
Under such conditions, a solid substance exists in equilibrium with its vapor instead of its liquid:
Under such conditions
前文の状況が発生する状況。condition は複数のパラメタが関与するので，複数形。
a solid substance exists in equilibrium with its vapor instead of its liquid:
二酸化炭素がそうですよね。常圧では「液体の」二酸化炭素は存在せず、ドライアイスから気体の
二酸化炭素への「昇華」が起こっています。
solid + heat energy →← vapor
The change of state from a solid directly to a gas is known as sublimation.
The change (of state) (from a solid directly to a gas) is known as sublimation.
Among the common substances that sublime at ordinary temperature are dry ice and iodine.
倒置，かな？とりあえず戻してみると
Among the common substances, dry ice and iodine are that sublime at ordinary temperature.
dry ice は「乾いた氷」ではなく「ドライアイス (固体 CO2)」です。
Ordinary ice sublimes slowly at temperatures lower than its melting point (0 ºC).
Ordinary ice sublimes slowly at temperatures which are lower than its melting point (0 ºC).
水の三重点 (triple point) は 0.01 ºC, 610.6 Pa (= 4.59 mmHg = 0.006 atm)
This is how a thin layer of snow can eventually disappear, despite the fact that the temperature remains below 0 ºC.
This is how ～：このようにして～が起こる。
0 ºC 以下ですから，雪が解けてなくなるわけではないのです。この場合，雪は昇華して消えていきます。
ロマンティクやねえ。
Frost-free refrigerators make use of sublimation by periodically slightly warming their freezer compartments, and then
using a blower to remove molecules of water as they sublime.
Frost-free refrigerators make use of sublimation by warming their freezer compartments,
by using a blower to remove molecules of water as they sublime.
Frost-free refrigerators：霜のつかない冷蔵庫
Phase Diagrams
The temperature and pressure conditions under which a substance exists in a given state can be conveniently
summarized in a phase diagram.
The temperature and pressure conditions can be conveniently summarized in a phase diagram.
under the conditions, a substance exists in a given state
A phase diagram is a graph of temperature versus pressure that indicates the conditions under which gaseous, liquid,
and solid phases of a particular substance exist.
A phase diagram is a graph of temperature versus pressure
the graph indicates the conditions
under the conditions, gaseous, liquid, and solid phases of a particular substance exist.
A phase diagram also reveals how the states of a system change with changing temperature or pressure.
A phase diagram also reveals ～
how the states of a system change with changing temperature or pressure.
change with ～：～とともに変わる。
Figure 13-17 shows the phase diagram for water over a range of temperatures and pressure conditions.
over a range of：ある範囲にわたって、かなあ
Note the three curves, AB, AD, and AC.
Each point on curve AC indicates the simultaneous temperature and pressure conditions under which liquid water and
water vapor can exist together at equilibrium.
Each point on curve AC indicates the simultaneous temperature and pressure conditions
simultaneous：水と水蒸気とが平衡状態になっている「まさにその時の」
under the conditions, liquid water and water vapor can exist together at equilibrium.
Similarly, curve AD indicates the temperature and pressure conditions under which ice and liquid water are in
equilibrium.
curve AD indicates the temperature and pressure conditions
under the conditions, ice and liquid water are in equilibrium.
Curve AB indicates the temperature and pressure conditions under which ice and water vapor coexist at equilibrium.
Curve AB indicates the temperature and pressure conditions
under the conditions, ice and water vapor coexist at equilibrium.
３つのカーブの説明をしているのですが、微妙に表現を変えていることに注意してください。
can exist together, in equilibrium, coexist
Point A is called the triple point of water.
The triple point of a substance indicates the temperature and pressure conditions at which the solid, liquid, and vapor of
the substance can coexist at equilibrium.
The triple point of a substance indicates the temperature and pressure conditions
at the conditions, the solid, liquid, and vapor of the substance can coexist at equilibrium.
上のカーブの説明を重ね合わせると、こうなりますわな。
Point C is called the critical point of water.
The critical point of a substance indicates the critical temperature (tc), the temperature above which the substance
cannot exist in the liquid state.
The critical point of a substance indicates the critical temperature (tc), or the temperature above which the
substance cannot exist in the liquid state.
or を補うと分かりやすいかな。
The critical point also indicates the critical pressure (Pc), the lowest pressure required for the substance to exist as a
liquid at the critical temperature.
The critical point also indicates the critical pressure (Pc), or the lowest pressure required for the substance to exist
as a liquid at the critical temperature.
The phase diagram in Figure 13-17 also indicates the normal boiling point and the normal freezing point of a substance.
1 atm のところを見ればよいのです。
As shown by the slope of line AD, ice melts at a higher temperature with decreasing pressure.
右下がりの曲線ですから。自分で確かめてください。
逆に，高圧下では氷の融点はより低くなります－ということは、その温度では氷は溶けているのです。
これが、アイススケートができる原理です。
As the temperature drops below the triple point, the temperature of sublimation decreases with decreasing pressure.
この図のどの部分を見ればいいですか？
The freeze-drying of foods is accomplished by vaporizing the ice and lowering the pressure after freezing.
昇華平衡線上に一点をとって，そこから温度を変えずに圧力を下げる (図で言うと真下に動く) と vapor
の領域に入るでしょう？固体の水 (氷) はここではどんどん「昇華」していくのです。
Figure13-17. The phase diagram for water.
Water vapor cannot be converted to a liquid beyond the critical temperature (374.1 ºC), no matter how high the pressure
exerted on the vapor.
beyond the critical temperature：374.1 ºC より高い温度ですか？低い温度ですか？絵でいうと、critical point
の右側ですか？左側ですか？具体的に考えましょう。
no matter how high：どんなに高くしたとしても
The critical pressure (218.3 atm) is the lowest pressure required for the substance to exist as a liquid at the critical
temperature.