Download Chemistry Final - Practice Test I

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Chemistry Final - Practice Test
I.
CLASSIFICATION OF MATTER
Define the following:
Elements: cannot be broken down further
Compound: elements that are chemically bonded together
Mixture:. elements/compounds physically mixed together
What is the difference between homogeneous and heterogeneous mixtures?
Homogenous: can’t see the parts (i.e. salt/water)
Heterogenous: can see the parts (i.e. sand/water)
Identify the following as elements, compounds, or mixtures:
Substance
As
NaCl
Sand +
Water
S
Air
E, C or M
E
C
M
E
M
State the Law of Conservation of Matter:
Mass/matter cannot be created or destroyed
Which of the following indicate a chemical change:
(a) fizzing
(b) burning
(c) color change
(d) all of the above
Which of the following are physical changes:
(a) state of changes (solid, liquid, gas)
(b) dissolving
(c) cracking open an egg
(d) all of the above
If 30g of KCl are added to 136g of water the resulting mass is _166g_.
II.
LABORATORY SAFETY
When should long hair be tied back?
Whenever fire is used, or dangerous chemicals
When chemicals are spilled what should you do? Call over the instructor immediately
III.
NUMBERS IN CHEMISTRY
What is the correct number of significant figures to leave in your final answer to these
calculations?
a. (3.0)(2.30) = 6.9
b. 2.3 + 3.44 = 5.7
c. 3.44 x 2.0 + 3.9 = 6.9 + 3.9 = 10.8
PEMDAS!!
Convert the following into scientific notation:
0.0035
3.5 x 10-3
43,025
4.3025 x 104
1
1 x 100
0.01
1 x 10-2
Express the following in standard (regular) notation:
36,000
3.6 x 104
4.9 x 10-2
0.049
How many significant figures do the following numbers have?
0.00321
3
320001
6
1.0000
5
.00210
3
There are 60 seconds per minute, 60 minutes per hour, 24 hours per day and 365 days per year. How
many seconds are in a year?
365days 24hours 60 min 60 sec
1 year 



 31,536,000 sec  30,000,000 sec
1 year
1day
1hour 1min
If 3.784 liters = 1 gallon, how many liters are in 4 gallons?
3.784 L
4 gallons 
 15L  20 L
1gallon
A field goal kicker who makes 20/21 field goals through the center of the uprights has:
(a) poor accuracy but good precision
(b) good accuracy and good precision
(c) poor accuracy and poor precision
(d) good accuracy and poor precision
What is the formula for density? What is the unit for density?
mass ( g )
Density 
volume (ml or cm 3 )
2
m
D
V
An unknown metal has the mass of 2.5g and a volume of 0.48mL. What is its density?
2.5 g
Density 
 5.2 g/mL
0.48mL
Define qualitative and quantitative measurements. Give an example of each.
Quantitative measurement:
Quantitative: numbers. I have three apples.
Qualitative measurement:
Qualitative: descriptive. I have a red apple.
What would be the best metric unit for measuring the diameter of a dime?
Centimeters or millimeters
Calculate the average atomic mass of silver if 51.83% of silver atoms occurring in nature have a mass of
106.905 amu and 48.17% of the atoms have a mass of 108.905 amu.
DON’T DO!! I DIDN’T TEACH YOU THIS!
IV.
ATOMIC STRUCTURE
What was the contribution to chemistry by each of these individuals?
Neils Bohr Developed the Planetary Model of the atom based on Quantum energy levels
Henry Moseley Arranged the Periodic Table – Increasing atomic number using x-rays and wavelengths
Rutherford Discovered that most of the atoms mass is located in the nucleus of an atom
JJ Thomson Discovered the electron and developed the plum pudding model of the atom.
Schrödinger Quantum mechanical model. Electrons can be found in clouds around the nucleus.
Democritous Believed that matter is composed of empty space in which atoms move.
Dalton Developed the first Atomic Theory of Matter. Developed the spherical model of the atom (or
billiard ball model)
Chadwick discovered the neutron
De Broglie Stated that electrons behave like waves.
Millikan Determined the charge of an electron. Oil drop experiment.
An atomic number is the same as the number of:
(a) neutrons
(b) electrons
(c) alpha particles
(d) protons
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An atom is defined as the smallest part of an element that:
(a) has protons, neutrons, and electrons
(b) has protons and neutrons
(c) retains the chemical identity of that element
(d) can form an ion
The atomic number (# of protons) and mass of chlorine are?
(a) 17, 35
(b) 33, 75
(c) 16, 32
(d) 29, 64
The neutrons of an atom are found:
(a) in the nucleus
(b) orbiting the nucleus
(c) in the s block
(d) in the orbitals
Which has the smallest mass?
(a) protons
(b) neutrons
(c) electrons
(d) ions
The number of protons always equals the number of
The mass number of an element tells you the # of
Who is credited with discovering:
The nucleus? Rutherford
The electron? JJ Thomson
The Planetary Model of the Atom?
electrons
in a neutral atom.
protons and neutrons .
Bohr
Isotopes have the same number of protons but different numbers of neutrons and different mass
numbers.
V.
PERIODIC TABLE AND PERIODIC TRENDS
a. Define these terms:
i. Reactivity:
ii. Atomic Radius: from the center of the atoms to the outershell (increases ↓ increases ←)
iii. Ionization Energy: energy req’d to remove an electron (increases ↑ increases →)
iv. Electronegativity: ability of an atom to attract an electron (increases ↑ increases →)
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b. Where can you locate the metals, non-metals, metalloids, alkali metals, alkaline earth metals,
transition metals, halogens and noble gases on the periodic table?
Metals: from left to right & under the staircase, Nonmetals: above staircase, Metalloids: along
staircase, Alkaline: Group 1, Alkaline Earth: Group 2, Transition metals: middle of periodic
table (d orbital block), Halogens: Group 7, Noble Gases: Group 8.
VI.
Ionic and Covalent Bonding
1. Naming Ionic Compounds
a. NH4Cl ammonium chloride
b. Fe(NO3)3 iron (III) nitrate
c. Cu3P copper (I) phosphide
d. Al(CN)3 aluminum cyanide
e. Pb(SO4)2 lead (IV) sulfate
2. Formula of Ionic Compounds
a. lead (II) nitride Pb+2 N-3  Pb3N2
b. silver bromide Ag+ Br-  AgBr
c. chromium (VI) phosphate Cr+6 (PO4)-3  Cr(PO4)2
*reduce your subscripts!*
d. vanadium (V) sulfide V+5 S-2  V2S5
e. potassium bicarbonate K+ HCO3-  KHCO3
3. Naming Covalent Compounds
a. IO2
iodine dioxide
b. C2Br6 dicarbon hexabromide
c. BBr3
boron tribromide
d. N2O3
dinitrogen trioxide
4. Formula of Covalent Compounds
a. tetraphosphorus triselenide
P4Se3
b. disilicon hexabromide
Si2Br6
c. diselenium diiodide
Se2I2
d. tetrasulfur dinitride
S4N2
5. Naming Gases
a. What are the seven diatomic molecules (name and formula)?
Nitrogen: N2, Oxygen: O2, Fluorine: F2, Chlorine: Cl2, Bromine: Br2, Iodine: I2
Hydrogen: H2
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VII.
Chemical Reactions
1. Provide a description for each type of chemical reaction.
a. Combustion Reaction
Carbon/hydrogen compound reacts with oxygen element to produce CO2 and H2O
CxHy + O2  CO2 + H2O
b. Synthesis Reaction
Element/Compound + Element/Compound combine to produce 1 PRODUCT!
A + B  AB
c. Decomposition Reaction
1 REACTANT breaks apart into smaller compounds or elements
AB  A + B
d. Single Replacement Reaction
Single element reacts with a compound to produce a new compound and a new single
element
A + BC  AC + B
e. Double Replacement Reaction
Compound reacts with a compound to produce TWO NEW compounds
AB + CD  AD + CB
2. Identify the type of chemical reaction using the following chemical equations. BALANCE.
a. 3 Mg + 1 Fe2O3  2 Fe + 3 MgO
Type of Reaction: Single Replacement
b. 1 C2H4 + 3 O2  2 CO2 + 2 H2O
Type of Reaction: Combustion
c. 2 PbSO4  2 PbSO3 + 1 O2
Type of Reaction: Decomposition
d. 1 H2O + 1 SO3  1 H2SO4
Type of Reaction: Synthesis
e. 1 H2SO4 + 2 NH4OH  2 H2O + 1 (NH4)2SO4
Type of Reaction: Double Replacemnt
VIII.
Predicting Products
1. Identify the type of reaction and predict the products and write a balanced chemical equation.
a. 2 Na + Cl2  2 NaCl
Synthesis
b. 2 KI  2 K + I2
Decomposition
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c. 3 Zn + Cu2(SO4)3  3 ZnSO4 + 2 Cu
Single Replacement
d. 2 NaOH + H2SO4  2 H2O + Na2SO4
Double Replacement
e. 2 C2H6 + 7 O2  4 CO2 + 6 H2O
Combustion
2. Definitions
a. Chemical Reaction
An atom of one or more substances are rearranged to form different substances
b. Law of Definite Proportions (not Law of Conservation of Matter)
A compound contains the same elements in exactly the same proportions by mass
regardless of the size of the sample or source of the compound.
c. Balanced Chemical Equation
Follows the law of conservation of matter/mass
3.
What is always equal on each side of the arrow in a balanced chemical equation?
# of atoms of each element
4. How many atoms are represented in the formula for Cr(CO3)3?
13 atoms total (1 Cr, 3 C, 9 O = 1 + 3 + 9 = 13)
5. Where are reactants and products found in a chemical equation?
Reactants: before the arrow. Products: after the arrow.
IX.
Percent Composition and Percent by Mass
a. What is the percent by mass of each element in CuSO4?
Cu : 1  64  64
%Cu : 64/160 *100  40%
S :1  32  32
%S : 32/160 *100  20%
O : 4  16  64
%O : 64/160 *100  40%
Total Compound Mass :160
b. What is the percent by mass of hydrogen in hydrogen chloride?
HCl is formula for hydrogen chloride
H :1  1  1
%H :1/36 *100  3%
Cl :1  35  35
Total Compound Mass : 36
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X.
GENERAL REVIEW
Convert the following (KHD B d c m)
1L = 1000mL
100cm = 1m
2735cg = 27.35g
What Metric unit is used to measure Mass?
Volume?
Length?
Temperature?
Grams
Liters
Meters
Kelvin
If the density of a substance is 25g/mL, what is the volume occupied by 300g of the substance?
mass
mass
D
; volume 
volume
density
300 g
Volume 
 12mL
25 g / mL
In normal processes can total energy be created or destroyed?
No
What differentiates a physical from a chemical change?
(a) A change in color
(b) Phase change
(c) Formation of a new substance
(d) Change in density
Circle the chemical changes below
Burning paper
Melting Ice
C6H12O6 + H2O  C6H12O6 + H2O
Ca + H2O  CaO + H2
Identify the following as an element, compound, or mixture.
a. mixture
b. element
c. compound
Identify the separation technique used in the following:
A process used to separate sand and water.
Filtration
An electrical process that can separate water into hydrogen and oxygen.
Electrolysis
Boiling a chemical and then condensing its vapors.
Distillation
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d. mixture
A solution is left sitting on the counter. After several days only a solid remains in the container.
Evaporization/Crystallization
Describe the separation technique that could be used to separate each of the following mixtures:
Two colorless liquids.
Distillation
Colored dye or ink.
Chromatography
A non- dissolving solid mixed with a liquid.
Filtration
If an atom has 14 protons, 15 neutrons and, 14 electrons; its complete chemical symbol would be
What is the atomic mass of chlorine gas, Cl2 70g
9
29
14
Si