Download 1st semester exam review

1st semester exam review
Chapter 1 Vocab
• Chemistry –
• Mass –
• Volume –
• Types of data:
– Qualitative – how something looks, feels,
sounds, tastes, smells
• Ex:
– Quantitative – uses numbers
• Ex:
• Independent variable – in an experiment,
the variable the experimenter plans to
change
• Dependent variable – the thing the
scientist measures
– Dependent on the independent variable
• Control – standard for comparison, does
not receive the independent variable
Chapter 2: Significant Figures
• all the digits that are known precisely plus
one last one that is estimated.
Rules for Significant Digits
1. Every nonzero digit is significant
Ex. 24.7 m
2. Zeros appearing between nonzero digits
are significant
Ex. 24.07 m
3. Zeros after significant digits are only
significant if there is a decimal point
Ex. 2470
Ex. 2470.0
4. Zeros in front of numbers are NOT
significant, even after a decimal point
Ex. 0.0000247
Ex. 0.247
5. When a number is in scientific notation, all
numbers in the coefficient are significant
Ex. 2.470 x 103
Significant Digits in Calculations
• An answer cannot be more precise than
the least precise measurement from which
it was calculated.
• To round off an answer you must first
decide how many significant digits the
answer should have.
• Your calculator DOES NOT keep track of
significant digits, you have to do it!
Addition & Subtraction
• Answer can have no more decimal
places than the number in the problem
with the fewest decimal places.
– Ex: 4.5 + 6.007 + 13.39 =
• Correct sig figs =
Multiplication & Division
• Answer can have no more significant
digits than the number in the problem with
the fewest significant digits
– Ex: 3.24 x 7.689 x 12.0 =
• Correct Sig. Figs =
Chapter 2 Vocab
• Temperature – quantitative measurement
of the average kinetic energy of the
particles that make up an object
• Accuracy - how close a single
measurement comes to the actual
dimension or true value of what is
measured
• Precision - how close several
measurements are to the same value
• Base unit – measurements that can be
taken with one instrument
– Time
– Length
– Mass
– Temperature
– Amount
Chapter 2: Density
• Density = amount of mass per unit volume
– Units =
• Always the same for a given substance
–D=
• What is the density of a cube that has a
mass of 29.8 g and a volume of 4.3 cm3?
• What is the mass of an object with a
density of 19.32 g and a volume of 2.568
cm3?
• What is the volume of an object with a
mass of 13.5 g and a density of 1.4 g/mL?
Chapter 2: Conversions
Convert 8.96L to milliliters
• Convert 525 km to cm
• Convert 365 miles/hr to feet/s
• Convert 15.9 m/s to km/h
Chapter 3
• Solids –
• Liquids –
• Gas –
Chapter 3: Physical Properties
• Characteristic that can be observed or
measured without changing the samples
composition
– Ex:
Chapter 3: Chemical Properties
• The ability of a substance to combine with
or change into one or more other
substances
• Magic word:
– Burning
– Iron rusting
– Inert gasses
Chapter 3: Physical Changes
• Alters a substance without changing its
composition
• Ex:
Chapter 3: Chemical Changes
• One or more substances changing into
new substances
• Chemical reactions
• New substances have different
composition & properties
• Decompose, explode, rust, oxidize,
corrode, burn
Chapter 3: Mixtures
• Heterogeneous mixture
• Homogeneous mixture
Chapter 3: Separating Mixtures
• Filtration – uses a porous barrier to
separate a solid from a liquid
• Distillation – separates a mixture whose
components have different boiling points
Chapter 3: Elements and
Compounds
• Element – pure substance that cannot be
separated into simpler substances
– Found on the periodic table
– Ex:
• Compounds – made up of two or more
elements that are chemically combined
– Represented by chemical formulas
– Ex:
Chapter 3: Laws
• Law of conservation of mass - Mass is
neither created nor destroyed during a
chemical reaction, it is conserved
– Mass of reactants = mass of products
• Law of definite proportions - A compound
is always composed of the same elements
in the same proportion by mass,
regardless of size of the sample
Chapter 4: Scientists
• J.J. Thomson:
– Discovered – Model = positively charged matter with
electrons dispersed throughout it
– Picture:
• Rutherford
– Discovered:
– Model = atom is mostly empty space with
positively charged nucleus & electrons flying
around it
– Picture:
• Chadwick
– Discovered -
Chapter 4: The atom
• Atom =
• Structure:
– Nucleus
– Outside nucleus
– Picture
• Isotopes = Atoms with
the same number of
protons but different
number of neutrons
• Which two are
isotopes of one
another?
P
N
E-
1
9
10 9
2
8
10 8
3
10 9
4
9
10
12 9
Chapter 4: Atomic Shorthand
• Beryllium- - -atomic number 4
mass number 9
• The mass number is written as a
superscript.
• The atomic number is written as a
subscript.
Be
Element
16
2O
8
27
13Al
80
35Br
3+
-
31 P315
39
+
K
19
Atomic
#
Protons
Neutrons
Electrons
Mass
number
Chapter 4: average atomic mass
• Unknown element X has two isotopes. 6X
has a 7.59 % abundance. 7X has a
92.41% abundance. What is the atomic
mass of the unknown element?
Chapter 5: Vocab
• Amplitude: Waves height from origin to
crest or origin to trough
• Wavelength (λ): Shortest distance
between equivalent points on a wave
• Frequency (ν): number of waves that pass
a given point per second
Chapter 5: Problems
• c = λν
• What is the wavelength of a microwave
that has a frequency of 3.44 x 109 Hz?
• E = hv
• What is the energy of a photon from violet
light if it has a frequency of 7.230 x 1014
Hz
• What kind of wave has a wavelength of
10-8 m?
• What kind of wave has a frequency of
1014 hZ?
Chapter 5: electron configurations
• What are the electron configurations of the
following?
– Co
– Kr
– Ba
Chapter 5: Dot Structures
• Dot structures show only the valence
electrons
• Valence electrons determine an atoms
properties
• Valence electrons & group:
• Draw the dot structures for the following
atoms:
–P
– Li
– Br
Chapter 6: Scientists
• Antoine Lavoisier
– Compiled first list of elements known at the
time (33 of them)
– Organized elements into four categories
1.
2.
3.
4.
• John Newlands
– Noticed when elements were arranged by
increasing atomic mass their properties
repeated every 8th element
• Pattern is periodic (repeats in a specific manner)
– Named this the law of octaves
• Dmitri Mendeleev
– Arranged elements in order of increasing
atomic mass into columns with similar
properties
• Henry Moseley
– Arranged table by atomic number
Chapter 6: Periodic Table
• S, p, d, f block
• Columns = groups
– Numbered 1 – 18
– Everything in the same group has the same
number of
• Rows = periods
– Numbered 1 – 7
• Use the electron configuration to
determine the group and period of the
following
– [Ne]4s23d104p4
• Metals
– Found:
– Good conductors of heat & electricity
– Malleable
– Ductile
• Nonmetals
– Found
– Poor conductors of heat and electricity
• Families
– Alkali metals
– Alkaline earth metals
– Transition metals
– Halogens
– Nobel gases
• Which family has electron configurations
that end in s2?
• Which family has electron configurations
that end in p5?
Chapter 6: Trends
• Electronegativity - The ability of an atom to
attract electrons in a chemical bond
– Within period – increases from left to right
– Within group – decreases from top to bottom
• Pick the element in each group that has
the highest electronegativity
– Li, B, N, O
– As, Se, Sb, Te
• Ionization energy - Energy required to
remove an electron from a gaseous atom
– Within period – increases from left to right
– Within group – decreases from top to bottom
• Pick the element in each group that has
the lowest ionization energy
– K, Ca, Se, Br
– Rb, Sr, Cs, Ba
• Atomic size
– Within period – decreases from left to right
– Within group – increases from top to bottom
• Ion size:
– Cations are always bigger than the neutral
atom
• Ex:
– Anions are always smaller than the neutral
atom
• Ex:
• In which group is the one on the left bigger
than the one on the right?
– F, F– Ca, Ca2+
– Li, Na
– N, B
Chapter 7: Vocab
• Chemical bond –
• Ionic compound – compound that contains
ionic bonds (electrons are lost/gained)
• Binary ionic compound –
Chapter 7: Properties
• Ionic Compounds
– High melting point
– High boiling point
– Hard, rigid, brittle solids
– Electrolytes only when dissolved or melted
not when solid
• Metals
– High melting points
– High boiling points
– Malleable & ductile
– Good conductors of heat and electricity
Chapter 7: Ratios
• Group 1 & group 17 =
– Ratio
• Group 2 & group 17 =
– Ratio
• Group 2 & group 15 =
– Ratio
Chapter 7: Naming
• Name the following:
– KOH
– Ca(NO3)2
– (NH4)3PO4
• Name the following:
– CuCl2
– CoN
– Hg3P2
• Give the formulas for the following:
– Calcium oxide
– Chromium (IV) Chlorite
– Sodium Nitride