AP CHEMISTRY: Foundations pre-QUIZ
Show ALL work and units. Neatly organize your work.
Atoms and Molecules
1.
Determine the missing values for each atom listed.
45
21
Sc3
79
35
Number of protons
Number of electrons
Number of neutrons
Atomic number
Atomic mass
_______
_______
_______
_______
_______
Br 1
Number of protons
Number of electrons
Number of neutrons
Atomic number
Atomic mass
_______
_______
_______
_______
_______
2. Write the valence electron configuration for
a. Se2b. Fe3+
3.
For each compound: draw the structure, state the geometry and state the polarity.
a. NH3
b. C2H5O
4.
Write and name the compound formed by the combination of these ions
a. Ca2+
+
O2-

b. Mn4+
+
SO32-

c. Mo6+
+
PO43-

d. Cr3+
+
NO31-

Conversions
5.
Ethylene gas, C2H4, is the ripening hormone in fruit. How many carbon atoms are contained in 5.00 mL of this gas at
STP?
6.
How many molecules of NO are in 12.05g of NO?
7.
A 5.0 mL sample of 0.50 M MgCl2 solution contains how many chloride ions?
8.
Convert 2.0 x1010 molecules of CO2 to grams of CO2
Significant Figures
9.
Express the answer to each of the following calculations with the correct number of significant figures.
a. 10 cm + 0.299 cm
b. (0.25 mm)(6.0 mm)
c. (0.25 mm)(6.0 mm) + (10 cm + 0.299 cm)
Reaction Prediction
10.
1
AP CHEMISTRY: Foundations pre-QUIZ
Equation Writing and Balancing
Balance each equation. Write the formulas where required.
11.
__NiO + __S8  __Ni +
12.
__Pt + __Ni2(SO3)3
13.
__H2O2  __H2O + __O2
__SO2
 __Pt(SO3)2 +
__Ni
14.
calcium nitrate →
15.
iron
+
sulfuric acid →
iron (III) sulfate
16.
nitrogen
+
magnesium →
magnesium nitride
calcium nitrite
+
oxygen
+
hydrogen
Determining Oxidation Numbers
Determine the oxidation number of the underlined atom. [Note – the overall charge of the molecule is equal to the sum
of the oxidation numbers of each individual atom]
Oxidation Number is the apparent charge of an atom in a molecule. Some oxidation numbers can often be found from
the atom’s location on the periodic table: Group 1 is +1, Group 2 is +2, H is +1 (or -1 in hydrides), O is -2 (-1 in
peroxides). In binary ionic compounds Group 17 is -1. Otherwise the oxidation number is calculated.
example: given, NaClO4, where Na = +1 (Group 1), O = -2,
since Na + Cl + 4 O = 0,
then Cl = +7.
Note: for a single atom the charge is the oxidation number.
17.
ClO31-
Cl =
18.
CoCl2
Co =
19.
K3PO4
P
=
20.
H2SO3
S
=
Molecular and Empirical Formulas
21.
22.
Determine the molecular formula of a substance that has the composition: 43.6% P and 56.4 % O, with a molecular
molar mass of ~142 g/mol, to determine the molecular formula.
A compound consists of 65.5%C, 5.49% H and the rest is O. Determine the empirical formula. Then, use the molar
mass of the empirical formula along with the fact that the compound has a molecular molar mass of ~165 g/mol, to
determine the molecular formula?
2
Acid Base Problems
23.
If a solution has a hydrogen ion concentration of 4.2 x 10-11 M, what is the pH of the solution?
24.
What is the pOH of a solution that has a hydrogen ion concentration, [H +], of 7.8 x 10-3?
Gas Law Problems
25. A syringe contains of 5.00 mL of air at 20 ˚C and 763 torr what will the temperature be if when plunger is pulled back and
the air is at 20.00 mL and 250 torr?
26. Air is primarily a mixture of nitrogen, N2, and oxygen, O2. Max fills a balloon with ammonia, NH3, and then hands the
balloon to Maggie who drops it. Where is the balloon? Explain
27. A student collects hydrogen gas over water (bubbling through water). What is the pressure of the hydrogen gas if the
atmospheric pressure is 772 mmHg and the water vapor pressure is 19.0 mmHg?
28. What is the density of carbon monoxide gas at 101.2 kPa and 21.0 ˚C?
Energy
A 44.0 g sample of a liquid at 11.0 ºC absorbs 18,750 J of heat until the temperature reaches the boiling point at 225 ºC. The
substance is then boiled.
29. What is the specific heat of the substance?
30. How much more heat must be absorbed to boil all of the liquid sample to a gas? {heat of vaporization: Hvap = 815
J
g
31. Some palm oil is burned beneath an aluminum container holding 90.0 g of water causing the temperature of the water to
increase from 12.0 °C to 54.0 °C. How many calories of heat were in the palm oil? Water’s specific heat is 1.00 gcalC .
Stoichiometry
32. How many grams of CuCO3 are produced when 11.51 g of Cu(NO3)2 are reacted with excess NaHCO3?
Cu(NO3)2 + 2 NaHCO3 
CuCO3
+ 2 NaNO3
+ H2O
+ 2 CO2
33. How many grams of KCl are produced when a 12.8 g sample of KClO 3 decomposes?
2 KClO3

3 O2
+
2 KCl
34. What mass of metallic silver is produced when a 2.95 mol sample of silver oxide decomposes?
2 AgO

2 Ag +
O2
Half-Life
 
This is not review, however if you know that for radioactive decay l n[A]   t n 2  t  n[A ] , where [ A ] is
 12 
the original concentration or mass, [A] is the present concentration or mass, t is time, and t 1/2 is the half-life.
35.
Sodium-24 has a half-life of 15.0 h. How long will it be before only 1/16 of the original sample of sodium-40 remains?
36.
A sample contains 2.400 kg of radioactive 60Co (half-life 5.26 y) on the day of Tommy’s birth. How much of this
isotope will remain on Tommy’s 21st birthday?
3
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