Question 1

What is the mass of 0.0250 mol of P2O5

Accepted Answer

A)  35.5 g 
B)  5676 g 
C)  0.0250 g 
D)  1.51 * 1022 g 
E)  3.55 g 
A)  35.5 g 
B)  5676 g 
C)  0.0250 g 
D)  1.51 * 1022 g 
E)  3.55 g

Question 2

Calculate the mass of excess reagent remaining at the end of the reaction in which 90.0 g of SO2 are mixed with 100.0 g of O2.2SO2 + O2 $\rarr$ 2SO3

Accepted Answer

A)  11.5 g 
B)  22.5 g 
C)  67.5 g 
D)  77.5 g 
E)  400 g 
A)  11.5 g 
B)  22.5 g 
C)  67.5 g 
D)  77.5 g 
E)  400 g

Question 3

An atom of helium has a mass about four times greater than that of an atom of hydrogen. Which choice makes the correct comparison of the redative numbers of helium and hydrogen atoms in equal masses of the two elements

Accepted Answer

A)  There are about four times as many helium atoms as hydrogen atoms. 
B)  There are about two times as many helium atoms as hydrogen atoms. 
C)  The number of helium and hydrogen atoms is the same. 
D)  There are about half as many helium atoms as hydrogen atoms. 
E)  There are about one-fourth as many helium atoms as hydrogen atoms. 
A)  There are about four times as many helium atoms as hydrogen atoms. 
B)  There are about two times as many helium atoms as hydrogen atoms. 
C)  The number of helium and hydrogen atoms is the same. 
D)  There are about half as many helium atoms as hydrogen atoms. 
E)  There are about one-fourth as many helium atoms as hydrogen atoms.

Question 4

A sample of iron metal is placed in a graduated cylinder. It is noted that 10.4 mL of water is displaced by the iron. The iron is then reacted with excess hydrochloric acid to produce iron (II) chloride and hydrogen gas. Given the density for iron is 7.86 g/mL, how many grams of iron (II) chloride are produced in the reaction
Fe(s) + 2HCl(aq) $\rarr$ FeCl2(aq) + H2(g)

Accepted Answer

A)  23.6 g 
B)  47.2 g 
C)  185 g 
D)  3.00 g 
E)  81.7 g 
A)  23.6 g 
B)  47.2 g 
C)  185 g 
D)  3.00 g 
E)  81.7 g

Question 5

Vanadium(V) oxide reacts with calcium according to the chemical equation below. When 10.0 moles of V2O5 are mixed with 10.0 moles of Ca, which is the limiting reagent
V2O5(s) + 5Ca(l) $\rarr$ 2V(l) + 5CaO(s)

Accepted Answer

A)  V2O5 
B)  Ca 
C)  V 
D)  CaO 
E)  No reagent is limiting. 
A)  V2O5 
B)  Ca 
C)  V 
D)  CaO 
E)  No reagent is limiting.

Question 6

Calculate the mass of 4.50 moles of Ca3PO4.

Accepted Answer

A)  215 g 
B)  968 g 
C)  0.0209 g 
D)  87.1 g 
E)  392 g 
A)  215 g 
B)  968 g 
C)  0.0209 g 
D)  87.1 g 
E)  392 g

Question 7

A compound with an empirical formula of C2H3Br2 has a molar mass of 373.69 g/mol. What is the molecular formula

Accepted Answer

A)  C2H3Br2 
B)  CHBr 
C)  C6H9Br6 
D)  C4H6Br2 
E)  C4H6Br4 
A)  C2H3Br2 
B)  CHBr 
C)  C6H9Br6 
D)  C4H6Br2 
E)  C4H6Br4

Question 8

How many moles of O are in 2.45 moles of H2CO3

Accepted Answer

A)  2.45 moles O 
B)  39.2 moles O 
C)  118 moles O 
D)  7.35 moles O 
E)  0.459 moles O 
A)  2.45 moles O 
B)  39.2 moles O 
C)  118 moles O 
D)  7.35 moles O 
E)  0.459 moles O

Question 9

Calculate the mass of FeS formed when 9.42 g of iron reacts with 8.50 g of sulfur according to the following reaction.Fe(s) + S(s) $\rarr$ FeS(s)

Accepted Answer

A)  17.9 g 
B)  87.9 g 
C)  26.0 g 
D)  14.8 g 
E)  1.91 * 10-3 g 
A)  17.9 g 
B)  87.9 g 
C)  26.0 g 
D)  14.8 g 
E)  1.91 * 10-3 g

Question 10

A chemistry student determined the empirical formula for titanium sulfide (TixSy). To do so, she reacted titanium with excess sulfur in a crucible, and recorded the following data: $\begin{array}{lr}
\text { Weight of crucible } & 11.120 \mathrm{~g} \
\text { Weight of titanium } & 8.820 \mathrm{~g} \
\text { Weight of crucible and product } & 31.700 \mathrm{~g}
\end{array}$ What is the empirical formula of titanium sulfide

Accepted Answer

A)  Ti2S 
B)  TiS3 
C)  TiS2 
D)  Ti3S2 
E)  None of the above 
A)  Ti2S 
B)  TiS3 
C)  TiS2 
D)  Ti3S2 
E)  None of the above

Question 11

How many F atoms are in 5.54 g of F2

Accepted Answer

A)  6.02 * 1023 atoms 
B)  0.146 atoms 
C)  0.292 atoms 
D)  8.78 * 1022 atoms 
E)  1.76 * 1023 atoms 
A)  6.02 * 1023 atoms 
B)  0.146 atoms 
C)  0.292 atoms 
D)  8.78 * 1022 atoms 
E)  1.76 * 1023 atoms

Question 12

What is the minimum mass of oxygen gas necessary to produce 200. g of sulfuric acid in the following reaction?
2SO2 + O2 + 2 H2O $\rarr$ 2H2SO4

Accepted Answer

A)  62.6 g 
B)  52.6 g 
C)  42.6 g 
D)  32.6 g 
E)  None of the above 
A)  62.6 g 
B)  52.6 g 
C)  42.6 g 
D)  32.6 g 
E)  None of the above

Question 13

The percent composition by mass of tartaric acid is: 32.01% C, 4.03% H, and 63.96% O. Given that the molecular mass of tartaric acid is 150 amu, determine its molecular formula.

Accepted Answer

A)  C5H6O6 
B)  C4H7O6 
C)  C4H6O6 
D)  C4H6O5 
E)  None of the above 
A)  C5H6O6 
B)  C4H7O6 
C)  C4H6O6 
D)  C4H6O5 
E)  None of the above

Question 14

The element oxygen consists of three naturally occurring isotopes: 16O, 17O, and 18O. The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes

Accepted Answer

A)  More than 50% of all O atoms are 17O. 
B)  Almost all O atoms are 18O. 
C)  Almost all O atoms are 17O. 
D)  The isotopes all have the same abundance, i.e. 33.3%. 
E)  The abundances of 17O and 18O are very small. 
A)  More than 50% of all O atoms are 17O. 
B)  Almost all O atoms are 18O. 
C)  Almost all O atoms are 17O. 
D)  The isotopes all have the same abundance, i.e. 33.3%. 
E)  The abundances of 17O and 18O are very small.

Question 15

Ammonium nitrate decomposes to give dinitrogen monoxide and water as shown in the following reaction: NH4NO3 $\rarr$ N2O + 2H2O
If a 108 g sample of NH4NO3 decomposes to give 23 g of N2O(g), what percent of the original sample remains

Accepted Answer

A)  69 % remains 
B)  61 % remains 
C)  59% remains 
D)  51 % remains 
E)  None of the above 
A)  69 % remains 
B)  61 % remains 
C)  59% remains 
D)  51 % remains 
E)  None of the above

Question 16

Which one of the following does not represent 1.000 mol of the indicated substance

Accepted Answer

A)  6.022 * 1023 C atoms 
B)  26.00 g Fe 
C)  12.01 g C 
D)  65.39 g Zn 
E)  6.022 * 1023 Fe atoms 
A)  6.022 * 1023 C atoms 
B)  26.00 g Fe 
C)  12.01 g C 
D)  65.39 g Zn 
E)  6.022 * 1023 Fe atoms

Question 17

How many Mg atoms are present in 170 g of Mg

Accepted Answer

A)  4.2 x 1024 
B)  3.5 x 1024 
C)  2.9 x 1024 
D)  1.7 x 1024 
E)  None of the above 
A)  4.2 x 1024 
B)  3.5 x 1024 
C)  2.9 x 1024 
D)  1.7 x 1024 
E)  None of the above

Question 18

Formaldehyde has the formula CH2O. How many molecules are there in 0.11 g of formaldehyde

Accepted Answer

A)  6.1 * 10-27 
B)  3.7 * 10-3 
C)  4.0 
D)  2.2 * 1021 
E)  6.6 * 1022 
A)  6.1 * 10-27 
B)  3.7 * 10-3 
C)  4.0 
D)  2.2 * 1021 
E)  6.6 * 1022

Question 19

Calculate the number of moles of cesium in 50.0 g of cesium.

Accepted Answer

A)  0.376 mol 
B)  0.357 mol 
C)  2.66 mol 
D)  2.80 mol 
E)  0.0200 mol 
A)  0.376 mol 
B)  0.357 mol 
C)  2.66 mol 
D)  2.80 mol 
E)  0.0200 mol

Question 20

Calculate the mass of O in 4.36 g of Cl2O7

Accepted Answer

A)  30.5 g O 
B)  48.8 g O 
C)  11.2 g O 
D)  69.8 g O 
E)  2.67 g O 
A)  30.5 g O 
B)  48.8 g O 
C)  11.2 g O 
D)  69.8 g O 
E)  2.67 g O

Exam 3: Mass Relationships in Chemical Reactions

What is the mass of 0.0250 mol of P2O5

Calculate the mass of excess reagent remaining at the end of the reaction in which 90.0 g of SO2 are mixed with 100.0 g of O2.2SO2 + O2 →\rarr→ 2SO3

An atom of helium has a mass about four times greater than that of an atom of hydrogen. Which choice makes the correct comparison of the redative numbers of helium and hydrogen atoms in equal masses of the two elements

Vanadium(V) oxide reacts with calcium according to the chemical equation below. When 10.0 moles of V2O5 are mixed with 10.0 moles of Ca, which is the limiting reagent V2O5(s) + 5Ca(l) →\rarr→ 2V(l) + 5CaO(s)

Calculate the mass of 4.50 moles of Ca3PO4.

A compound with an empirical formula of C2H3Br2 has a molar mass of 373.69 g/mol. What is the molecular formula

How many moles of O are in 2.45 moles of H2CO3

Calculate the mass of FeS formed when 9.42 g of iron reacts with 8.50 g of sulfur according to the following reaction.Fe(s) + S(s) →\rarr→ FeS(s)

How many F atoms are in 5.54 g of F2

What is the minimum mass of oxygen gas necessary to produce 200. g of sulfuric acid in the following reaction? 2SO2 + O2 + 2 H2O →\rarr→ 2H2SO4

The percent composition by mass of tartaric acid is: 32.01% C, 4.03% H, and 63.96% O. Given that the molecular mass of tartaric acid is 150 amu, determine its molecular formula.

The element oxygen consists of three naturally occurring isotopes: 16O, 17O, and 18O. The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes

Ammonium nitrate decomposes to give dinitrogen monoxide and water as shown in the following reaction: NH4NO3 →\rarr→ N2O + 2H2O If a 108 g sample of NH4NO3 decomposes to give 23 g of N2O(g), what percent of the original sample remains

Which one of the following does not represent 1.000 mol of the indicated substance

How many Mg atoms are present in 170 g of Mg

Formaldehyde has the formula CH2O. How many molecules are there in 0.11 g of formaldehyde

Calculate the number of moles of cesium in 50.0 g of cesium.

Calculate the mass of O in 4.36 g of Cl2O7

Chemistry: The Study of Change

Atoms Molecules and Ions

Reactions in Aqueous Solutions

Gases

Thermochemistry

Quantum Theory and the Electronic Structure of Atoms

Periodic Relationships Among the Elements

Chemical Bonding I: Basic Concepts

Chemical Bonding II: Molecular Geometry and Hybridization of Atomic

Intermolecular Forces and Liquids and Solids

Physical Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria and Solubility Equilibria

Entropy Free Energy and Equilibrium

Electrochemistry

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Chemistry in the Atmosphere

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Nonmetallic Elements and Their Compounds

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Filters

What is the mass of 0.0250 mol of P₂O₅

Calculate the mass of excess reagent remaining at the end of the reaction in which 90.0 g of SO₂ are mixed with 100.0 g of O₂.2SO₂ + O₂ $\rarr$ 2SO₃

Vanadium(V) oxide reacts with calcium according to the chemical equation below. When 10.0 moles of V₂O₅ are mixed with 10.0 moles of Ca, which is the limiting reagent V₂O₅(s) + 5Ca(l) $\rarr$ 2V(l) + 5CaO(s)

Calculate the mass of 4.50 moles of Ca₃PO₄.

A compound with an empirical formula of C₂H₃Br₂ has a molar mass of 373.69 g/mol. What is the molecular formula

How many moles of O are in 2.45 moles of H₂CO₃

Calculate the mass of FeS formed when 9.42 g of iron reacts with 8.50 g of sulfur according to the following reaction.Fe(s) + S(s) $\rarr$ FeS(s)

How many F atoms are in 5.54 g of F₂

What is the minimum mass of oxygen gas necessary to produce 200. g of sulfuric acid in the following reaction? 2SO₂ + O₂ + 2 H₂O $\rarr$ 2H₂SO₄

The element oxygen consists of three naturally occurring isotopes: ¹⁶O, ¹⁷O, and ¹⁸O. The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes

Ammonium nitrate decomposes to give dinitrogen monoxide and water as shown in the following reaction: NH₄NO₃ $\rarr$ N₂O + 2H₂O If a 108 g sample of NH₄NO₃ decomposes to give 23 g of N₂O(g), what percent of the original sample remains

Formaldehyde has the formula CH₂O. How many molecules are there in 0.11 g of formaldehyde

Calculate the mass of O in 4.36 g of Cl₂O₇