WorksheetsChemistry Spring Semester Exam 23-24
Total questions: 80
Worksheet time: 43mins
What is the total number of atoms in 1 mole of NH₃?
17.04 atoms
2 atoms
6.02X10²³ atoms
1.03X10²⁵ atoms
What is the molar mass of C₂H₆?
30.08 g/mol
31 moles
13.02 g
6.02X10²³ molecules
What is the mass of Oxygen if you have 4 moles of Oxygen? (Reminder this is a diatomic element)
60 g/mol
135 g/mol
128 g/mol
71 g/mol
What is the number of moles in 25 grams of CaCO₃?
1 mole
2 mole
0.1 mole
0.2 mole
What is the percent by mass of carbon in acetone, C3H6O?
20.7%
30.0%
1.61%
62.1%
Calculate the percent composition of calcium acetate, Ca(C2H3O2)2.
40.0% Ca; 48.0% C; 4.0% H; 64.0% O
25.4% Ca; 30.4% C; 3.8% H; 40.5% O
25.0% Ca; 25.0% C; 4.5% H; 45.5% O
21.1% Ca; 30.0% C; 7.8% H; 42.1% O
What calculations can you perform if you know the molar mass of a compound?
Converting moles of a compound to grams
Converting grams of the compound to moles
Both A and B
Neither A nor B
To determine the formula of a new substance, one of the first steps is to find the
volume at STP.
percent composition.
molar mass.
number of particles per mole.
If 20.0 grams of Ca combines completely with 16.0 grams of S to form a compound, what is the percent composition of Ca in the compound?
1.25%
55.6%
20.0%
44.4%
If 60.2 grams of Hg combines completely with 24.0 grams of Br to form a compound, what is the percent composition of Hg in the compound?
28.5%
60.1%
71.5%
39.9%
What is the percent composition of chromium in BaCrO4?
4.87%
20.5%
25.2%
9.47%
Calculate the percent composition of the compound that forms when 222.6 g N combines completely with 77.4 g O.
81.0% N; 19.0% O
74.2% N; 25.8% O
22.6% N; 77.4% O
65.2% N; 34.8% O
What is the percent composition of carbon, in heptane, C7H16?
19%
68%
12%
84%
Chemical reactions can be described in terms of what quantities?
Numbers of atoms, molecules, or moles
Mass
Volume
All of the above
How are mole ratios used in chemical calculations?
As evidence that a chemical reaction obeys the law of conservation of mass
To demonstrate whether or not the balanced chemical equation obeys the law of conservation of mass
To convert between a given number of moles of reactant or product to moles of a different reactant or product
To determine whether a reactant or product exists as a solid, liquid, gas, or aqueous solution
How many grams of SO₃ are produced when 20.0 g FeS₂ react with 16.0 g O₂ according to this balanced equation? 4FeS₂(s) + 15O₂(g) → 2Fe₂O₃(s) + 8SO₃(g)
21.4 g SO₃
26.6 g SO₃
32.0 g SO₃
37.1 g SO₃
What is the percent yield if 4.65 g of copper are produced when 1.87 g of aluminum react with an excess of copper(II) sulfate? 2Al(s) + 3CuSO₄(aq) → Al₂(SO₄)₃(aq) + 3Cu(s)
6.61%
40.2%
66.1%
70.5%
The combustion of acetylene gas is represented by this equation: 2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O(g) How many moles of H₂O are produced when 64.0 g C₂H₂ burn in oxygen?
2.00 moles H₂O
2.46 moles H₂O
4.92 moles H₂O
5.13 moles H₂O
Sodium reacts with water to produce sodium hydroxide and hydrogen gas in the reaction shown below. 2Na + 2H₂O → 2NaOH + H₂ What mass of hydrogen gas is produced when 13.2 mol Na reacts with excess water?
6.60 g
13.2 g
26.4 g
None of these
Iron reacts with antimony sulfide to produce antimony and iron(II) sulfide by the reaction shown below. Sb₂S₃(s) + 3Fe(s) → 2Sb(s) + 3FeS(s) What mass of iron is needed to react with excess antimony sulfide to produce 2,680 g antimony?
818 g
1,790 g
1,840 g
4,020 g
A student combines 15.0 g FeS₂ with excess O₂, which react according to the balanced equation shown below. From this information and using the molar masses of the reactants and products, what information can the student calculate about the reaction? 4FeS₂(s) + 15O₂(g) → 2Fe₂O₃(s) + 8SO₃(g)
The theoretical yield of each product
The actual yield of each product
The theoretical yield, actual yield, and percent yield of each product
The theoretical yield of Fe₂O₃, but not SO₃
A student reacts 3.4 moles of aluminum with excess water according to the following equation: 2Al(s) + 6H2O(g) → 2Al(OH)3(s) + 3H2(g). How many moles of hydrogen gas will the reaction produce?
1.7 moles
2.3 moles
3.4 moles
5.1 moles
The calculation of quantities in chemical equations is called ____.
stoichiometry
dimensional analysis
percent composition
percent yield
In the reaction 2CO(g) + O2(g) → 2CO2(g), what is the ratio of moles of oxygen used to moles of CO2 produced?
1:1
2:1
1:2
2:2
How many moles of glucose, C6H12O6, can be "burned" biologically when 10.0 mol of oxygen is available? C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2O(l)
0.938 mol
1.67 mol
53.3 mol
60.0 mol
The equation below shows the decomposition of lead nitrate. How many grams of oxygen are produced when 11.5 g NO2 is formed? 2Pb(NO3)2(s) → 2PbO(s) + 4NO2(g) + O2(g)
1.00 g
2.00 g
2.88 g
32.0 g
Iron(III) oxide is formed when iron combines with oxygen in the air. How many grams of Fe2O3 are formed when 16.7 g of Fe reacts completely with oxygen? 4Fe(s) + 3O2(g) → 2Fe2O3(s)
12.0 g
23.9 g
47.8 g
95.6 g
When glucose is consumed, it reacts with oxygen in the body to produce carbon dioxide, water, and energy. How many grams of carbon dioxide would be produced if 45 g of C6H12O6 completely reacted with oxygen? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
1.5 g
1.8 g
11 g
66 g
Mercury can be obtained by reacting mercury(II) sulfide with calcium oxide. How many grams of calcium oxide are needed to produce 36.0 g of Hg? 4HgS(s) + 4CaO(s) → 4Hg(l) + 3CaS(s) + CaSO4
1.80 g
7.56 g
10.1 g
13.4 g
How many grams of chromium are needed to react with an excess of CuSO₄ to produce 27.0 g Cu?
14.7 g
18.0 g
33.2 g
81.5 g
How many grams of beryllium are needed to produce 36.0 g of hydrogen? (Assume an excess of water.)
4.00 g
36.0 g
162 g
324 g
What is the maximum number of grams of PH₃ that can be formed when 6.2 g of phosphorus reacts with 4.0 g of hydrogen to form PH₃?
0.43 g
6.8 g
270 g
45 g
Lead nitrate can be decomposed by heating. What is the percent yield of the decomposition reaction if 9.9 g Pb(NO₃)₂ are heated to give 5.5 g of PbO?
44%
56%
67%
82%
In a particular reaction between copper metal and silver nitrate, 12.7 g Cu produced 38.1 g Ag. What is the percent yield of silver in this reaction?
56.7%
77.3%
88.2%
176%
When a gas temperature increase, the particles move
slower
depends on the volume and temperature
at the same speed
faster
At 0 Kelvin
Gas particles have no potential energy and the volume of a gas is theoretically zero
gas particles stop moving and the potential energy of a gas is zero
Gas particles stop moving and the volume of gas is theoretically zero
none are the answer
The volume of a gas is a good measure of the amount (mass of the gas
under any conditions
at fixed temperature and pressure
at fixed temperature
at fixed pressure
A student shakes a sealed, full can of carbonated soda. What is the best way to open the can safely?
Heat the can because this will decrease the pressure
heat the can because this will increase the pressure
refrigerate the can because this will decrease the pressure
refrigerate the can because this will increase the pressure
How do you double the volume of a gas without changing the temperature or amount of it?
double the pressure
half the pressure
quadruple the pressure
quarter the pressure
Calculate the pH of the solution: [OH⁻] = 1 × 10⁻²M
11.0
12.0
2.0
2.1
How is an acid defined by the Brønsted-Lowry theory?
An acid dissolves in water to produce hydrogen ions.
An acid dissolves in water to produce hydronium ions.
An acid donates a hydronium ion in a chemical reaction.
An acid donates a hydrogen ion in a chemical reaction.
What is the range of pH values in a basic solution?
pH is greater than 7
pH = 7
pH is between 0 and 14
pH is less than 7
An aqueous solution has a hydrogen-ion concentration of 5.0 × 10⁻⁶M. What is the pH of the solution?
5.3
6.0
6.3
5.0
Find the hydroxide-ion concentration for a solution with pH = 12.00.
1.0 × 10⁻¹⁰M
1.2 × 10⁻⁷M
1.0 × 10⁻²M
1.0 × 10⁻¹²M
What is the Arrhenius definition of an acid and a base?
An acid contains hydrogen; a base contains a hydroxide group (OH⁻).
An acid ionizes to yield hydrogen ions (H⁺) in aqueous solution; a base ionizes to yield hydroxide ions (OH⁻) in aqueous solution.
An acid ionizes in water to yield a positive cation and a negative anion; a base dissolves in water without ionizing.
An acid donates hydrogen ions (H⁺); a base receives hydrogen ions.
Find the hydroxide-ion concentration for a solution with pH = 6.00
6.0 × 10⁻⁶ M
6.0 × 10⁻¹ M
1.0 × 10⁻⁸ M
1.0 × 10⁻⁶ M
What is the range of pH values in an acidic solution?
pH is greater than 7
pH = 7
pH is between 0 and 14
pH is less than 7
What is the range of pH values in a basic solution?
pH is less than 7
pH = 7
pH is between 0 and 14
pH is greater than 7
The concentration of hydrogen ions in a soil sample is 1.3 × 10⁻⁶M. When the soil is tested with a pH meter, what value should the meter read?
1.3
1.9
5.9
6.2
Calculate the pH of the solution: [H+] = 0.00010M
4.00
10.00
4.50
3.00
Calculate the pH of a solution with the following hydrogen-ion concentration: [H+] = 1 × 10^-6M
8.6
4.0
-6.0
6.0
What methods can you use to measure the pH of a solution?
Observing color or clarity
Measuring density or electrical conductivity
Measuring mass or volume
Using acid base-indicators or pH meters
What is the range of pH values in a neutral solution?
pH is between 0 and 14
pH = 7
pH is less than 7
pH is greater than 7
Which equation defines the pH of a solution?
pH = 10[H+]
pH = 7 + log[H+]
pH = -log[H+]
pH = -[H+]
What are the products of a reaction between an acid and a base?
Carbon dioxide and a salt
Another acid and base
Either two acids or two bases
Water and a salt
Find the hydroxide-ion concentration for a solution with pH = 9.00.
1.0 x 10^9M
9.0 x 10^-1M
5.0 x 10^-6M
1.0 x 10^-5M
How did Lewis broaden the definition of acids and bases?
He defined acids and bases according to their reaction with water molecules.
He defined an acid as an electron-pair donor and a base as an electron-pair acceptor.
He defined an acid as a hydrogen-ion donor and a base as a hydrogen-ion acceptor.
He defined an acid as an electron-pair acceptor and a base as an electron-pair donor.
How are [H+] and the pH of a solution related?
[H+] increases as pH increases.
[H+] decreases as pH increases.
[H+] increases as pH decreases.
Both B and C
When radium-226 (atomic number 88) decays by emitting an alpha particle, it becomes ____.
radium-222
polonium-222
polonium-224
radon-222
Which form of radiation, if any, has the greatest penetrating power, and generally is the most dangerous?
Alpha Radiation
Beta Radiation
Gamma Radiation
None of the above; the answer varies
with the source of the radiation
The mass of cobalt-60 in a sample decreased from 0.800 g to 0.200 g over a period of 10.5 years. From this
information, calculate the half-life of cobalt-60.
2.12 years
5.25 years
4.00 years
0.400years
A radioisotope has a half-life of 4 days. How much of a 20-gram sample of this radioisotope remains at the
end of 8 days?
10 grams
2 grams
12 grams
5 grams
Which statement best describes a positron?
A proton that has been ejected from an atomic nucleus
A particle like an electron, but carrying a positive charge instead of a negative charge
A particle like a neutron, but carrying a positive charge instead of no charge
A parcel of energy like a photon, but carrying a positive charge
When polonium-210 decays by alpha radiation, what isotope is formed?
Lead - 208
Bismuth - 210
Lead - 206
Radon - 214
How does beta decay affect the mass number of a nucleus?
decreased by 2
decreased by 4
increase by 1
no change
How is the atomic number of a nucleus changed by beta decay?
increase by 1
decreased byt 2
decreased by 1
increased by 2
What is the charge on a particle of beta radiation?
+1
-1
0
+2
What is the charge on a particle of alpha radiation?
0
+2
+1
-1
What is the change in atomic mass when an atom emits gamma radiation?
Mass remains the same
Mass decreases by 2.
Mass increases by 1.
Mass decreases by 1.
How does alpha decay affect the mass number of a nucleus?
a. Decreases by 4 c. Decreases by 6
b. Decreases by 2 d. Increases by 2
decreased by 4
decreased by 2
decreased by 6
increased by 2
A radioisotope has a half-life of 4 days. How much of a 20-gram sample of this radioisotope remains at the
end of 4 days?
16 grams
5 grams
2 grams
10 rams
What is the change in atomic mass when an atom emits a beta particle?
Mass does not change
Mass decreases by 1
Mass increases by 1
Mass decreases by 2
How is the atomic number of a nucleus changed by gamma decay?
Decreases by 2
Decreases by 1
Increased by 2
No Change
How is the atomic number of a nucleus changed by alpha decay?
Decreases by 2
Decreases by 1
Increased by 2
Increased by 1
What particle is needed to complete this nuclear reaction?
86Rn222 --> 84Po218 + _____
2He4
-1e0
1H1
0n1
Plutonium-244 undergoes transmutation to become uranium-240. In the nuclear equation that describes this
transmutation, what particle is included, and where?
An alpha particle, as a product
A beta particle, as a product
An alpha particle, as a reactant
A beta particle, as a reactant
Match the following
the reactant that determines the amount of product that can be formed in a reaction
limiting reagent
the reactant that is not completely used up in a reaction
excess reagent
the amount of product formed when a reaction is carried out in the laboratory
actual yield
the ratio of the actual yield to the theoretical yield
percent yield
the maximum amount of product that could be formed from given amounts of reactants
theoretical yield
Match the following
P x V = n x R x T
Ideal Gas law
For a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure.
Boyles Law
At constant volume and temperature, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases.
Dalton Law
The volume of a fixed mass of gas is directly proportional to its Kelvin temperature, if the pressure is kept constant.
Charles Law
The pressure of a gas is directly proportional to its Kelvin temperature if the volume is kept constant.
Gay-Lussac Law
