Download IB Chemistry Summer Assignment Summer 2013

Name:
IB Chemistry Summer Assignment
Summer 2013
This packet is due the first day of class.
(HW completion)
Special thanks to Mr. Turner of RMHS!
NAMES AND CHARGES OF COMMON IONS
Reference Information
MONATOMIC IONS
Group 1
+1
Li+
Na+
K+
Rb+
Cs+
Group 2
+2
Be2+
Mg2+
Ca2+
Sr2+
Ba2+
Transition Metals:
Group 3
+3
B3+
Al3+
Ga3+
Group 5
-3
N3P3-
Group 6
-2
O2S2-
Group 7
-1
FClBrI-
Many can form more than one monatomic ion
cadmium Cd2+
chromium Cr3+
cobalt Co2+ and Co3+
copper Cu+ and Cu2+
iron Fe2+ and Fe3+
lead Pb2+ and Pb4+
manganese Mn2+
gold Au
mercury (I) Hg22+ and (II) Hg2+
nickel Ni2+
silver Ag+
titanium Ti2+ , Ti3+ and Ti4+
tin Sn2+ and Sn4+
zinc Zn2+
POLYATOMIC IONS
+1
ammonium NH4
-1
+
acetate CH3COO
-2
-
-3
2-
carbonate
CO3
chlorate ClO3-
chromate
CrO42-
chlorite ClO2-
dichromate Cr2O72-
cyanide CN-
oxalate C2O42-
hydroxide OH-
peroxide O22-
hypochlorite ClO-
silicate SiO32-
iodate IO3-
sulfate SO42-
nitrate NO3-
sulfite SO32-
nitrite NO2-
thiosulfate S2O32-
perchlorate ClO4permanganate MnO4-
2
phosphate PO43-
TOPIC 1. SCIENTIFIC MEASUREMENTS AND CALCULATION SKILLS
•
•
•
•
•
•
•
•
Know from memory the 7 base SI units (name and symbol)
Know from memory the SI prefixes (symbol and multiplier) from giga down through nano
Know from memory the SI derived units for density, volume, concentration, pressure & energy
Know the definitions of accuracy vs. precision, and how to calculate percent error.
Be able to apply the rules for significant digits: writing, rounding and calculating
Be able to inter-convert units using dimensional analysis (sometimes called the factor label or
“picket fence” method)
Be able to express numbers and do calculations using scientific notation.
Be able to manipulate logarithms and inverse logarithms on your calculator (remember pH?).
PROBLEMS:
1. How many significant digits are shown in each of these measurements?
a. 27.3 g _________
e. 65.089 g
b. 0.013 cm
_________
f. 23.00m
c. 16.30 mL
_________
g. 100.78 kg
d. 0.0005 moles ________
h. 0.01050M
__________
__________
__________
__________
2. Perform the following conversions. Round answers to the correct number of significant digits and express in
scientific notation.
a. 0.19 km to cm
________________
f. 105.9 Ms to s ___________________
b. 5.75 g to kg ________________
g. 2.400 mm to m
___________________
c. 25.0 mL to L ________________
h. 1.606 kg to mg
___________________
d. 7.450 g to mg
i. 2.70 g/cm3 to kg/m3___________________
________________
e. 6.50 x 102 nm to m ________________
j. 125 mL to dm3
___________________
3. Write these numbers in scientific notation and round to the given number of “sig figs”:
a. 15,678 m (3 sig figs)
_____________
b. 0.001278 (2 sig figs)
_____________
c. 6,000 g
(4 sig figs)
_____________
d. 0.09809m (3 sig figs)
_____________
4. A student measures a small piece of aluminum foil. The length is 8.252 cm, and the width is 3.44 cm. She should
report the area of the foil as
______________________. If the aluminum foil were precut by industrial machines
using high precision, the actual area should have been 11.75 cm2, what was the student’s percent error? Also, convert
to m2.
3
5. Calculate, using sig figs: a) (8.753 x 10-13) (5.5 x108)
6.022 x 1023
___________________
b) (8.753 x 10-12) - (5.5 x10-13)
6.022 x 1023
___________________
6. The SI unit for gas pressure is the Pascal (Pa), equal to a force of 1 Newton acting on a surface of 1m2.
Since the Pascal is a very tiny unit of pressure, we usually use kiloPascals, or kPa. However, non-SI units are also used:
atmospheres (atm), mm Hg, and torr. The conversion factors are:
1 standard atmosphere (atm) = 101.3 kPa = 760 mm Hg = 760 torr.
Complete the the following conversions:
a. 745 mm Hg to kPa ___________
c. 235 kPa to atm
__________________
b. 87 mm Hg to atm ____________
d. 5.00 atm to torr
__________________
SHOW ALL WORK USING DIMENSIONAL ANALYSIS; UNDERLINE/ BOX ANSWERS.
7. A pile of chemistry books used over the summer to prepare for IB chemistry weighs 158.0 lbs. If 1 kg = 2.204 lbs,
what is the mass of this pile of knowledge in milligrams?
8. Take your height in inches, and convert it to your height in kilometers.
9. The true (literature) value for the density of aluminum is 2.70 g/cm3. Two students measure the density of a small
aluminum cylinder in the lab to be 2.45 g/cm3. Calculate the percent error, and explain what this means.
10. A pure gold coin has a diameter of 2.22 cm and is 2.40 mm thick. The density of gold is 19.32 g/cm3. If the price of
gold is $1800.00 per ounce (1 ounce = 28.35 g), how much money is the coin worth?
11. The concentration or strength of an acid solution is often express as pH. The definition of pH is:
pH = - log (H+ concentration)
+
a. If the H concentration in a sample of acid rain is 1.5 x 10-4 , what is the pH? ___________
b. If the pH of swimming pool water is 8.4, what is the [H+] and [OH-]?
4
____________
TOPIC 2: MATTER AND ENERGY
•
•
•
•
•
Be able to classify matter into categories. Know the definitions/difference between the terms substance,
element, compound, mixture, solution, homogeneous and heterogeneous.
Differentiate and give examples of physical properties vs chemical properties of a substance.
Be familiar with energy units: Joule, calorie, and Calorie.
Know the definition of specific heat capacity (Cp)
Solve energy problems using the heat transfer equation.
PROBLEMS:
1. Classify each type of matter by writing all the letters that apply to it in the blank:
S = substance
Ho = homogeneous mixture
E = element
Ht = heterogeneous mixture
C = compound
Sl = solution
air
________________________
sea water
________________________
_____________________
brass
________________________
pure distilled water ______________
pizza
________________________
oxygen gas (O2) ________________
methane
________________________
glucose
zinc
________________________
mercury
_______________________
pure table salt (NaCl) _________________________
gasoline
__________________
2. You are given a test tube containing an unknown liquid. Name four physical properties of this liquid you could
measure. Name two chemical properties. Also, what equipment could you use to measure these properties?
3. A candy bar label says that it contains 450 Calories. How many Joules of energy is this?
4. A Styrofoam cup containing 50.0 g of water is placed in a microwave oven and heated for 30 seconds. The
temperature rises from 25.0 oC to 58.0 oC. How much heat (J) did the water absorb?
5
TOPIC THREE: ATOMS, IONS AND CHEMICAL FORMULAS
•
•
•
•
•
•
Memorize the names, formulas and charges of common ions (see separate sheet)
Be able to name the three basic sub-atomic particles, their mass, charge and general location within
the atom.
Know the difference between an atom and an ion.
Given the name of an ionic compound, write its chemical formula (from memory).
Given the chemical formula of an ionic compound, write its correct name.
Know the meaning of the term isotope. Given the symbol of an isotope, identify its particles.
PROBLEMS
1. Fill in the blanks:
SYMBOL
# Protons
# Electrons
# Neutrons
Na+
_________
__________
__________
Cl-
_________
__________
__________
Iron-56
_________
__________
__________
Fe3+
_________
__________
__________
S2-
_________
__________
__________
Chlorine-37
_________
__________
__________
2. Write the correct chemical formula:
potassium chloride
______________
sodium hypochlorite
_____________
magnesium bromide
______________
potassium sulfate
_____________
iron (III) oxide
______________
sulfur (VI) oxide
_____________
barium phosphate
______________
sodium nitrate
_____________
potassium carbonate
______________
copper (II) hydroxide
_____________
potassium permanganate
______________
sodium oxide
_____________
ammonium phosphate
______________
silver carbonate
_____________
tin (IV) bromide
______________
chromium (VI) oxide
_____________
3. Write the correct names of the following compounds:
MgCO3
__________________________________________
CuCl
__________________________________________
Sc(NO3)3
__________________________________________
RbO
__________________________________________
6
NH4NO3
__________________________________________
ZnCl2
___________________________________________
Ag3PO4
________________________________________________________________
Li2CO3
___________________________________________
Ba(OH)2
___________________________________________
Al2(SO4)3
___________________________________________
KClO3
___________________________________________
ZnCrO4
___________________________________________
4. Write isotopic notation for these isotopes:
a. carbon-14
_____________
b. uranium-235 ___________
c. magnesium-25
_______________
d. iron-56
_______________
5. A certain element exists as three different isotopes, with the masses and percentages shown here:
Mass
Mass
Mass
64
66
68
49.0 %
27.8 %
23.0 %
Calculate the average atomic mass of this element, and identify it with its symbol from the periodic table.
TOPIC 4. CHEMICAL EQUATIONS
•
Be able to write and balance and classify chemical equations.
BALANCE THE FOLLOWING EQUATIONS
1.
____C2H2 (g)
+
____O2 (g)
2.
____BaCl2 (aq) + ____K3PO4 (aq)
3.
____Al (s)
+
____Cl2(g)
4.
____K (s)
+
____H2O (l)




____CO2 (g)
+
____H2O (g)
____Ba3(PO4)2 (s) + ____KCl
____AlCl3 (s)
____H2 (g)
7
+
____KOH (aq)
5.
____Fe2O3 (s)
+
6.
____NaClO3 (s)
7..
____H2O2 (aq)
8.
____Al(s)
9. .
____K (s)
10.
____Na (s)


+
+
____Fe (s)

+
____O2 (g)
+
____NaCl (s)
____O2 (g)
+
____H2O (l)
____ZnCl2(aq)
____Zn(s)

+
____ H2O (l) 
____KOH (aq)
____CaCl2(aq) +
____Na3PO4(aq) 
____Ca3(PO4)2(s)
11.
____C2H2 (g)
+
____O2 (g)
12.
____Na (s)
+
____C (s)
13.
____P +
14.
____C2H6O +
____O2(g)

15.
____AgNO3 +
____Na2SO4 
____NaNO3 +
____O2(g)
____CO2 (g)

+
____O2 (g)


____Na2O (s)
____AlCl3(aq)
+
____H2 (g)
+
+
____NaCl(aq)
____H2O (g)
____Na2CO3 (s)
____P2O5
____CO2
+ ____
H2 O
____Ag2SO4
2. Write balanced equations for these reactions. (Hint: Make sure you write correct formulas first, then worry about
the coefficients!!).
a. propane gas burns in an outdoor barbecue grill.
b. solid silver oxide decomposes when heated to form solid silver and oxygen gas.
c. a TUMS tablet containing solid calcium hydroxide reacts with hydrochloric acid in a person’s stomach to produce
water and aqueous calcium chloride.
d. Acid rain containing aqueous sulfuric acid reacts with the marble (calcium carbonate) carvings on the walls of a
cathedral to produce carbon dioxide, water, and solid calcium sulfate.
e. sodium metal reacts vigorously with water to produce hydrogen gas and aqueous sodium hydroxide.
8
f. In the space shuttle, carbon dioxide from the astronaut’s breathing is filtered thru a filter containing solid lithium
peroxide, and the products are solid lithium carbonate and oxygen gas.
g. Aqueous solutions of silver nitrate and solid sodium chloride are mixed. A white precipitate forms. (In your
equation, indicate which product is the precipitate).
h. Aqueous solutions of barium nitrate and ammonium sulfate are mixed. A white precipitate forms. (Indicate which
product is the precipitate).
TOPIC 5: THE MOLE CONCEPT AND CHEMICAL FORMULAS
• Be familiar with the concept of a mole as the fundamental “counting unit” of chemistry:
-- one mole of a substance contains 6.02 x 1023 particles of that substance
-- one mole of a substance has a definite mass called its molar mass
• Be able to interconvert between grams, moles and atoms of a given substance
• Be able to calculate the percent composition of a substance
• Be able to calculate the empirical formula of a substance
PROBLEMS
1. Convert grams of substance to moles.
a. 222 g Cu metal
c. 65.7 g of glucose
e.
75.0 g of (NH4)2CO3
______________
_________________________________________
______________
b.
500 g of water ______________
d.
25.O g of AgNO3
______________
f.
3.2 x 10-3 g of Fe2O3
______________
2. Convert moles to grams.
a. 1.50 x 10-3 moles NaOH
___________________
b. 2.50 moles NH3
___________________
c. 0.346 moles of CuSO4
___________________
3. A pure gold coin has a mass of 15.00 grams. How many gold atoms are there in the coin?
9
4. What is the percent composition of CuSO4? (In other words, what percentage of this substance, by mass, is due to
copper, sulfur, and oxygen, respectively?)
5. What mass (g) of aluminum oxide (Al203) will contain 50.0 g of aluminum? How many moles of aluminum oxide?
EMPIRICAL AND MOLECULAR FORMULAS
6. Chlorofluorocarbons, or “CFCs” are now banned because they can degrade the ozone layer in the atmosphere. One
such chemical is called freon. A sample of freon consists of 5.70 grams of fluorine, 10.65 grams of chlorine, and 1.79
grams of carbon. Calculate the empirical formula of freon.
7. Nicotine is the poisonous compound found in tobacco leaves. The nicotine molecule consists of
74 % carbon, 8.65 % H, and 17.35 % nitrogen. Determine the empirical formula.
8. A substance used in developing black-and-white photo film has a molar mass of 174 g/mole. It consists of 26.4 %
sodium, 36.9 % sulfur, and 36.7 % oxygen. Determine both the empirical and the molecular formula.
9. A hydrate is an ionic compound that has a certain number of water molecules bonded inside the crystal. For
example, copper sulfate pentahydrate has the formula CuSO4 * 5 H2O, indicating that there are five water molecules for
every formula unit of CuSO4, (or 5 moles of H2O per mole of CuSO4. Heating a hydrate compound drives off the water,
leaving the anyhydrous (“without water”) compound.
10
10. Strontium hydroxide exists as a hydrate having the formula Sr(OH)2 * X H2O, where “X” is a small whole number.
Suppose 10.00 grams of this hydrate is heated to drive off the water; the resulting anhydrous compound has a mass of
4.58 grams. Determine the value of “X” and write the formula for the hydrate.
TOPIC 6: BASIC STOICHIOMETRY
• Be able to solve basic mass-mass and mass-volume stoichiometry problems
PROBLEMS:
1. The emergency oxygen system in some jetliners is based upon a decomposition reaction of sodium chlorate
(NaClO3):
2 NaClO3
 3 O2 (g) +
2 NaCl (s)
As the reaction equation shows, when a canister of sodium chlorate is heated, it decomposes to form oxygen gas and
sodium chloride. If each passenger requires 450 grams of oxygen gas in an emergency, how many grams of sodium
chlorate must be provided for each passenger?
2. Aluminum metal reacts with aqueous zinc nitrate to form zinc metal and aluminum nitrate.
The equation is
2 Al (s) +
3 Zn(NO3)2 (aq) 
3 Zn (s)
+ 2 Al(NO3)3(aq)
a. Starting with 7.50 grams of aluminum metal, how many grams of zinc can be formed?
b. Starting with this same amount of aluminum, how many grams of zinc nitrate will be needed?
3. Referring to problem #2 above, if you started with 7.50 grams of aluminum and 7.90 grams of zinc nitrate, how much
zinc metal would be produced?
11
4. The compound called trinitrotoluene, or “TNT”, is an explosive. When TNT detonates, it forms many different
products, as shown in this balanced equation:
2 C 7H 5N 3O 6
TNT
12 CO (g)

+
5 H2 (g)
+ 3 N2 (g)
+
2 C (s)
a. If a block of TNT with a mass of 5.00 x 102 g explodes, how many grams of nitrogen gas will be formed?
b. If there were 4.00 x 102 g of carbon dioxide available, would all of the TNT be used up? Why or why not?
The next three questions refer to the combustion reaction of propane gas (C3H8) shown here:
C3H8 (g)
+
5 O2 (g)

3 CO2 (g)
+
4 H2O (g)
+
150 kJ
3. How many grams of water will be formed by burning 75.0 g of propane?
4. What volume of carbon dioxide, measured at standard temperature and pressure (STP) will also be formed when this
amount (75.0 g) of propane is burned? (Recall: 1 mole of any gas at STP has a volume of 22.4 Liters).
5. How much heat energy (Joules) will be given off when this amount of propane is burned? (Hint: the equation shows
you how much heat is given off when 1 mole of propane is burned).
TOPIC 7: ELECTRON STRUCTURE OF THE ATOM AND ORGANIZATION OF THE
PERIODIC TABLE OF THE ELEMENTS
• Given an element between H and Kr, be able to write its complete electron configuration.
• Be able to state the basic principles by which the modern Periodic Table of the Elements is organized.
PROBLEMS
1. Identify the element:
a. Electron configuration is 1s22s22p5
b. Electron configuration is 1s22s22p63s23p64s23d6
12
c. Electron configuration is [Ar] 4s2
d. Electron configuration ends in --4p4
2. Write the electron configuration for these elements:
a. sodium
________________________
b. zinc
________________________
c. neon
________________________
d. fluorine
________________________
e. nitrogen
________________________
3. State how many unpaired electrons these atoms have:
a. lithium
_______
c. carbon
b. nitrogen
_______
d. zinc
_______
_______
4. State how many valence electrons these atoms have:
a. carbon
_______
c. phosphorus
b. sulfur
_______
d. krypton
________
________
5. Organization of the Periodic Table
a. In what order are the elements arranged? ____________________________________
b. What is significant about the electron configuration of two elements that are in the same group (vertical
column) of the Table?
c. What can you say about the chemical properties of elements in the same Group?
d. List four
alkali metals
alkaline earth metals
halogens
TOPIC 8: CONCENTRATION OF SOLUTIONS (Molarity)
•
Know the definition of molarity and be able to calculate molarity of solutions.
PROBLEMS:
1. 50.0 g of NaCl are dissolved in water to make 250. mL of solution.
a. Calculate the molarity.
b. If the same mass of NaCl is dissolved in 250. g of water (remember the density of water = 1g/ cm3; 1 cm3 = 1 mL),
what is the molality?
13
2. What mass of silver nitrate do you need to make 250. mL of a 0.0150 M solution?
3. What volume (mL) of 1.50 M CuSO4 solution will contain 16.5 g of CuSO4?
4. You have 250 cm3 of a silver nitrate solution that is 2.00 M concentration. You dilute the solution until the total
volume is now 1000 cm3. What is the new concentration?
TOPIC 9: THE BEHAVIOR OF GASES
1. A 8.00 L fire extinguisher contains nitrogen gas at a pressure of 1.25 x 105 kPa and temperature of 35.0 oC. What
volume will this gas occupy as standard temperature and pressure (STP)?
2. A 50.0 cm3 sample of gas has a pressure of 98.5 kPa at 25.0 oC. How many moles of gas does this sample contain?
3. Several years ago, a frozen mummy was found in the Italian alps. This ancient man was carrying an axe made of
copper. Early man made copper by heating copper oxide ore (CuO) with charcoal (carbon) in campfires:
2 CuO
+ C 
2 Cu (s) + CO2 (g)
What volume of carbon dioxide gas, measured at STP, will be produced from the reaction of
530 g of copper oxide ore?
4. A tank contains a mixture of four gases. The amount of each gas is shown below. The total pressure of the mixture
is 2400 pascals. What is the partial pressure of each gas?
Helium = 2 moles
Oxygen = 1.5 moles
Ammonia = 3.0 moles
Carbon dioxide = 1.5 moles
14
5. Calculate the density of propane gas (C3H8) at STP.
TOPIC 10: STRUCTURE AND SHAPE OF MOLECULES
For each molecule, draw the correct Lewis electron dot structure. Then use the VSEPR concept to predict the shape of
the molecule: bent, triangular pyramid, triangular planar, tetrahedron, or linear.
Molecule
Lewis Structure
Shape (Geometry/ Name)
H2 O
NH3
CH2O
SbF6
HCN
SiCl4
O3
PCl5
15
TOPIC 11: ACIDS AND BASES
1. Write two chemical equations, illustrating the Arrhenius definition of an acid and a base.
2. What is the Brønsted-Lowry vs. Lewis definition of an acid and a base?
3. Label each species as A (acid), B (base), CA (conjugate acid), or CB (conjugate base).
A. NH3 (g)
+
B. CH3OH (aq)
C. OH- (aq)
+
H2O (l)
+
NH4+ (aq)

NH2- (aq)
HSO4-(aq)


+
OH-(aq)
CH3O- (aq) +
SO42- (aq) +
NH3 (g)
H2O (l)
4. Write correct chemical formulas for the following
a. conjugate acid of water
_________________
b. conjugate acid of the chloride ion
_________________
c. conjugate base of acetic acid
_________________
d. two conjugate bases of sulfuric acid ______________________
TOPIC 12: THERMODYNAMICS
1. A change in temperature from 10 °C to 20 °C is found to double the rate of a given chemical reaction. How did this
change affect the reacting molecules?
(A) It doubled their average velocity.
(B) It doubled their average energy.
(C) It doubled the number of collisions per second.
(D) It doubled the proportion of molecules possessing at least the minimum energy required for the reaction.
16
2. The rate equation for a chemical reaction is determined by
(A) theoretical calculations.
(B) measuring reaction rate as a function of concentration of reacting species.
(C) determining the equilibrium constant for the reaction.
(D) measuring reaction rates as a function of temperature.
3. The value of the rate constant of a reaction can generally be expected to
(A) be independent of temperature.
(B) increase with increasing temperature.
(C) decrease with increasing temperature.
(D) decrease with increasing temperature only if the reaction is
exothermic.
4. Which line in the diagram represents the activation energy for a forward
reaction?
(A) (B) (C) (D)
5. The rate law for the reaction A + B → C + D is first order in [A] and second order in [B]. If [A] is halved and [B] is
doubled, the rate of the reaction will
(A) remain the same.
(B) be increased by a factor of 2.
(C) be increased by a factor of 4.
(D) be increased by a factor of 8.
6. In a chemical reaction involving the formation of an intermediate activated complex, which step must always be
exothermic?
(A) Reactants → products
(B) Products → reactants
(C) Reactants → activated complex
(D) Products → activated complex
(E) Activated complex → products
7. The addition of a catalyst in a chemical reaction
(A) increases the concentration of products at equilibrium.
(B) increases the fraction of reactant molecules with a given kinetic energy.
(C) provides an alternate path with a different activation energy.
(D) lowers the enthalpy change in the overall reaction.
8. A catalyst will
(A) alter the pathway (mechanism) of a chemical reaction.
(B) increase ΔH for the reaction.
(C) decrease ΔH for the reaction.
(D)decrease Ea for the forward reaction only
9. The following mechanism has been proposed for the formation of ethylbenzene:
For the mechanism provided, which substance serves as the
catalyst?
(A) AlBr3
(B) AlBr4–
(C) CH3CH2+
(D) C6H6CH2CH3+
17
11. The table presents data for the reaction:
12. What is the rate law for this reaction?
(A) rate = k1 [H2 ] [NO]
(C) rate = k1 [H2]2 [NO]
(B) rate = k1 [H2 ]2 [NO]2
(D) rate = k1 [H2] [NO]2
13. In which reaction will an increase in total pressure at constant temperature favor formation of the products?
14. The equilibrium constant for the gaseous reaction C + D  E + 2F is 3.0 at 50 °C. In a 2.0 L flask at 50 °C
are placed 1.0 mol of C, 1.0 mol of D, 1.0 mol of E, and 3.0 mol of F. Initially, the reaction will:
(A) proceed at equal rates in both directions.
(B) proceed more rapidly to form E and F.
(C) proceed more rapidly to form C and D.
(D) not occur in either direction.
15. Consider this reaction.
The conditions of temperature and pressure that favor the formation of CO2 are:
(A) high T and high P.
(C) low T and high P.
(B) high T and low P.
(D) low T and low P.
16. For the reaction
2SO2(g) + O2(g)  2SO3(g) ΔH = –198 kJ
carried out at constant volume, the concentration of O2 at equilibrium will increase if
(A) SO2 is added to the system.
(B) SO3 is added to the system.
(C) the temperature of the system is lowered.
18
(D) an inert gas is added to the system.
17. Which factor would cause a change in the equilibrium constant, Kc, for this reaction?
2NOCl(g)  2NO(g) + Cl2(g)
(A) adding NO(g)
(B) decreasing the volume of the reaction vessel
(C) cooling the system
(D) adding an inert gas
18. A 1.20-L flask contains an equilibrium mixture of 0.0168 mol of N2, 0.2064 mol of H2, and 0.0143 mol of
NH3. Calculate the equilibrium constant, Kc for the reaction
N2(g) + 3H2(g)  2NH3(g)
(A) 1.38
(B) 1.99 (C) 4.12
(D) 4.96
19. Given the exothermic reaction:
N2(g) + 3H2(g)  2NH3(g) ΔH = –92.1 kJ
At 400 K, the equilibrium constant is 0.53. At 800 K, what is the value of the equilibrium constant; what does that mean?
19