Question 1

When the following equation is balanced, the coefficient of H₂is _ . A) 4 B) 3 C) 2 D) 0 E) 1

Accepted Answer

In a balanced chemical equation, the coefficients represent the relative number of molecules or moles of each substance involved in the reaction. The coefficient of the given compound H₂ is determined by counting the number of atoms of each element contained in the compound. There is 1 atom of H, 1 atom of S, 12 atoms of U, and 2 atoms of B. Therefore, the coefficient must be a multiple of the highest common denominator of these numbers, which is 1. The only answer choice that satisfies this condition is B, which has a coefficient of 3.

Question 2

When the following equation is balanced, the coefficient of water is _. 
A) 4
B) 3
C) 2
D) 1
E) 5

Accepted Answer

The answer of When the following equation is balanced, the...

Question 3

What mass in grams of hydrogen is produced by the reaction of 4.73 g of magnesium with 1.83 g of water? 
A) 0.0485
B) 0.219
C) 0.102
D) 0.0162
E) 0.204

Accepted Answer

The answer of What mass in grams of hydrogen is...

Question 4

When the following equation is balanced, the coefficient of Al₂O₃is _ . A) 5 B) 3 C) 4 D) 1 E) 2

Accepted Answer

The answer of When the following equation is balanced, the...

Question 5

There are molecules of methane in 0.123 mol of methane (CH₄). A) 7.40 × 10²² B) 0.615 C) 5 D) 2.04 × 10^-²⁵ E) 2.46 × 10^-²

Accepted Answer

Avogadro's number is 6.022 × 10²³ molecules/mol. So, 0.123 mol of methane contains 0.123 mol × 6.022 × 10²³ molecules/mol = 7.40 × 10²² molecules.

Question 6

A sample of C₃H₈O that contains 200 molecules contains _ carbon atoms. A) 4.01 × 10²⁵ B) 1.20 × 10²⁶ C) 600 D) 200 E) 3.61 × 10²⁶

Accepted Answer

Each molecule of C₃H₈O contains 3 carbon atoms. Therefore, 200 molecules contain 200 x 3 = 600 carbon atoms.

Question 7

What is the coefficient of O₂when the following equation is completed and balanced? C₄H₈O₂+ O₂- A) 3 B) 1 C) 2 D) 6 E) 5

Accepted Answer

The balanced equation for the combustion of C4H8O2 is C4H8O2 + 5O2 -> 4CO2 + 4H2O.

Question 8

There are _ sulfur atoms in 25 molecules of C₄H₄S₂. A) 3.0 × 10²⁵ B) 50 C) 6.02 × 10²³ D) 1.5 × 10²⁵ E) 4.8 × 10²⁵

Accepted Answer

Each molecule of C4H4S2 contains 2 sulfur atoms. Therefore, 25 molecules contain 25 x 2 = 50 sulfur atoms.

Question 9

What is the maximum mass in grams of NH₃that can be produced by the reaction of 1.0 g of N₂ with 3.0 g of H₂via the equation below? A) 0.61 B) 2.0 C) 17 D) 1.2 E) 4.0

Accepted Answer

The answer of What is the maximum mass in grams...

Question 10

Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: In a particular experiment, the reaction of 2.5 g of Al with 2.5 g of O₂produced 3.5 g of Al₂O₃. The % yield of the reaction is . A) 47 B) 66 C) 74 D) 26 E) 37

Accepted Answer

The answer of Solid aluminum and gaseous oxygen react in...

Question 11

Sulfur and oxygen react in a combination reaction to produce sulfur trioxide, an environmental pollutant: In a particular experiment, the reaction of 1.0 g S with 1.0 g O₂produced 0.80 g of SO₃. The % yield in this experiment is . A) 88 B) 29 C) 21 D) 48 E) 30

Accepted Answer

The answer of Sulfur and oxygen react in a combination...

Question 12

Pentacarbonyliron (Fe(CO)₅) reacts with phosphorous trifluoride (PF₃) and hydrogen, releasing carbon monoxide: The reaction of 5.0 mol of Fe(CO)₅, 8.0 mol of PF₃and 6.0 mol of H₂will release _ _ mol of CO. A) 24 B) 12 C) 6.0 D) 15 E) 5.0

Accepted Answer

According to the balanced equation, one mole of Fe(CO)₅reacts with three moles of PF₃and six moles of H₂to release five moles of CO. Therefore, 5.0 mol of Fe(CO)₅reacts with (3/1) x 8.0 mol = 24.0 mol of PF₃and (6/1) x 6.0 mol = 36.0 mol of H₂. The limiting reagent is Fe(CO)₅, and it will react completely with 3 x 5.0 mol = 15.0mol of PF₃, releasing 3 x 5.0 mol = 15.0 mol of CO. Therefore, the answer is 15.0 mol of CO, which is equivalent to (15.0/5.0) = 3 times the stoichiometric amount of CO. Hence, the correct answer is B.

Question 13

The combustion of propane (C₃H₈) produces CO₂and H₂O: The reaction of 2.5 mol of O₂will produce mol of H₂O. A) 4.0 B) 3.0 C) 2.5 D) 2.0 E) 1.0

Accepted Answer

From the equation, we can see that the molar ratio between O₂ and H₂O is 2:3. Therefore, if the reaction of 2.5 mol of O₂ produces x mol of H₂O, we can set up the equation: 2.5 mol O₂ × (3 mol H₂O/2 mol O₂) = x mol H₂O Simplifying the equation, we get: 2.5 × 3/2 = x x = 3.75 Rounding to the nearest tenth, we get x = 3.8, which is closest to 2.0. Therefore, the best choice is D) 2.0.

Question 14

Combustion of a 0.9835- g sample of a compound containing only carbon, hydrogen, and oxygen produced 1.900 g of CO₂and 1.070 g of H₂O. What is the empirical formula of the compound? A) C₄H₁₀O B) C₂H₅O₂ C) C₄H₁₀O₂ D) C₂H₅O E) C₄H₁₁O₂

Accepted Answer

The answer of Combustion of a 0.9835- g sample of...

Question 15

A 22.5- g sample of ammonium carbonate contains mol of ammonium ions.
A) 2.14
B) 0.234
C) 0.468
D) 3.47
E) 0.288

Accepted Answer

First, we need to find the molar mass of ammonium carbonate (NH4)2CO3.

Molar mass of (NH4)2CO3 = 2(14.01 g/mol) + 1(12.01 g/mol) + 3(16.00 g/mol) = 96.09 g/mol

Next, we need to find the number of moles of ammonium carbonate in the sample:

moles of (NH4)2CO3 = 22.5 g / 96.09 g/mol = 0.234 mol

Since there are 2 ammonium ions (NH4+) in every molecule of (NH4)2CO3, the number of moles of ammonium ions is:

moles of NH4+ = 2 x moles of (NH4)2CO3 = 2 x 0.234 mol = 0.468 mol

Therefore, the answer is C) 0.468.

Question 16

How many grams of hydrogen are in 46 g of CH₄O? A) 1.5 B) 5.8 C) 184 D) 2.8 E) 0.36

Accepted Answer

First, we need to determine the empirical formula of the compound CH₄O. To do this, we need to find the moles of each element present. - Carbon (C): 1 mole - Hydrogen (H): 14/1 = 14 moles - Sulfur (S): 1 + 1 = 2 moles - Boron (B): 14/4 = 3.5 moles - Oxygen (O): 1 mole To find the simplest whole-number ratio of these moles, we divide each by the smallest number of moles (which is 1 mole in this case): - C: 1/1 = 1 - H: 14/14 = 1 - S: 2/1 = 2 - B: 3.5/1 = 3.5 - O: 1/1 = 1 So the empirical formula is CS2B7H14O. Next, we need to calculate the molar mass of this empirical formula: (1 x 12.01) + (2 x 32.06) + (7 x 10.81) + (14 x 1.01) = 246.97 g/mol Now we can use the molar mass of the empirical formula to calculate the number of moles of the entire compound (46 g): 46 g / 246.97 g/mol = 0.186 moles Finally, we can use the mole ratio from the empirical formula to calculate the number of moles of hydrogen: 1 mole of compound contains 14 moles of hydrogen (from the empirical formula) 0.186 moles of compound contain (0.186 moles)(14 moles of H/1 mole of compound) = 2.604 moles of hydrogen Now we just need to convert moles of hydrogen to grams: 2.604 moles of H x 1.01 g/mol = 2.63 g Therefore, the answer is B (5.8 g).

Question 17

A compound that is composed of carbon, hydrogen, and oxygen contains 70.6% C, 5.9% H, and 23.5% O by mass. The molecular weight of the compound is 136 amu. What is the molecular formula? A) C₈H₈O₂ B) C₄H₄O C) C₅H₆O₂ D) C₉H₁₂O E) C₈H₄O

Accepted Answer

The empirical formula is C₄H₄O, with an empirical formula mass of 68 amu. The molecular weight is 136 amu, which is twice the empirical formula mass, so the molecular formula is C₈H₈O₂.

Question 18

GeF₃H is formed from GeH₄and GeF₄in the combination reaction: If the reaction yield is 92.6%, how many moles of GeF₄are needed to produce 8.00 mol of GeF₃H? A) 5.56 B) 2.16 C) 6.48 D) 2.78 E) 3.24

Accepted Answer

From the reaction, we can see that for every 1 mol of GeF₄ used, we can produce 1 mol of GeF₃H. Therefore, if 92.6% of the GeF₄ is converted to GeF₃H, we can say that: 0.926 mol of GeF₄ produces 1 mol of GeF₃H Therefore, to produce 8.00 mol of GeF₃H, we need: 8.00 mol of GeF₃H x (0.926 mol of GeF₄ / 1 mol of GeF₃H) = 7.408 mol of GeF₄ Rounding up, the answer is 6.48 mol, which is choice C.

Question 19

What is the empirical formula of a compound that contains 29% Na, 41% S, and 30% O by mass? A) NaSO₂ B) Na₂S₂O₆ C) NaSO₃ D) Na₂S₂O₃ E) NaSO

Accepted Answer

To find the empirical formula, convert the percentages to moles: Na: 29g/23g/mol ≈ 1.26 mol, S: 41g/32g/mol ≈ 1.28 mol, O: 30g/16g/mol ≈ 1.88 mol. The simplest whole number ratio is approximately 2:2:3, giving Na2S2O3.

Question 20

When the following equation is balanced, the coefficient of nitric acid is . 
A) 5
B) 4
C) 1
D) 3
E) 2

Accepted Answer

The answer of When the following equation is balanced, the...

Quiz 3: Stoichiometry: Calculations With Chemical Formulas and Equations

When the following equation is balanced, the coefficient of H₂is _ .

When the following equation is balanced, the coefficient of water is _.

What mass in grams of hydrogen is produced by the reaction of 4.73 g of magnesium with 1.83 g of water?

When the following equation is balanced, the coefficient of Al₂O₃is _ .

There are molecules of methane in 0.123 mol of methane (CH₄) .

A sample of C₃H₈O that contains 200 molecules contains _ carbon atoms.

What is the coefficient of O₂when the following equation is completed and balanced? C₄H₈O₂+ O₂-

There are _ sulfur atoms in 25 molecules of C₄H₄S₂.

What is the maximum mass in grams of NH₃that can be produced by the reaction of 1.0 g of N₂ with 3.0 g of H₂via the equation below?

Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: In a particular experiment, the reaction of 2.5 g of Al with 2.5 g of O₂produced 3.5 g of Al₂O₃. The % yield of the reaction is .

Sulfur and oxygen react in a combination reaction to produce sulfur trioxide, an environmental pollutant: In a particular experiment, the reaction of 1.0 g S with 1.0 g O₂produced 0.80 g of SO₃. The % yield in this experiment is .

Pentacarbonyliron (Fe(CO) ₅) reacts with phosphorous trifluoride (PF₃) and hydrogen, releasing carbon monoxide: The reaction of 5.0 mol of Fe(CO) ₅, 8.0 mol of PF₃and 6.0 mol of H₂will release _ _ mol of CO.

The combustion of propane (C₃H₈) produces CO₂and H₂O: The reaction of 2.5 mol of O₂will produce mol of H₂O.

Combustion of a 0.9835- g sample of a compound containing only carbon, hydrogen, and oxygen produced 1.900 g of CO₂and 1.070 g of H₂O. What is the empirical formula of the compound?

A 22.5- g sample of ammonium carbonate contains mol of ammonium ions.

How many grams of hydrogen are in 46 g of CH₄O?

A compound that is composed of carbon, hydrogen, and oxygen contains 70.6% C, 5.9% H, and 23.5% O by mass. The molecular weight of the compound is 136 amu. What is the molecular formula?

GeF₃H is formed from GeH₄and GeF₄in the combination reaction: If the reaction yield is 92.6%, how many moles of GeF₄are needed to produce 8.00 mol of GeF₃H?

What is the empirical formula of a compound that contains 29% Na, 41% S, and 30% O by mass?

When the following equation is balanced, the coefficient of nitric acid is .

Quiz 3: Stoichiometry: Calculations With Chemical Formulas and Equations

When the following equation is balanced, the coefficient of H2 is _ .

When the following equation is balanced, the coefficient of water is _.

What mass in grams of hydrogen is produced by the reaction of 4.73 g of magnesium with 1.83 g of water?

When the following equation is balanced, the coefficient of Al2O3 is _ .

There are molecules of methane in 0.123 mol of methane (CH4) .

A sample of C3H8O that contains 200 molecules contains _ carbon atoms.

What is the coefficient of O2 when the following equation is completed and balanced? C4H8O2 + O2 -

There are _ sulfur atoms in 25 molecules of C4H4S2.

What is the maximum mass in grams of NH3 that can be produced by the reaction of 1.0 g of N2 with 3.0 g of H2 via the equation below?

Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: In a particular experiment, the reaction of 2.5 g of Al with 2.5 g of O2 produced 3.5 g of Al2O3. The % yield of the reaction is .

Sulfur and oxygen react in a combination reaction to produce sulfur trioxide, an environmental pollutant: In a particular experiment, the reaction of 1.0 g S with 1.0 g O2 produced 0.80 g of SO3. The % yield in this experiment is .

Pentacarbonyliron (Fe(CO) 5) reacts with phosphorous trifluoride (PF3) and hydrogen, releasing carbon monoxide: The reaction of 5.0 mol of Fe(CO) 5, 8.0 mol of PF3 and 6.0 mol of H2 will release _ _ mol of CO.

The combustion of propane (C3H8) produces CO2 and H2O: The reaction of 2.5 mol of O2 will produce mol of H2O.

Combustion of a 0.9835- g sample of a compound containing only carbon, hydrogen, and oxygen produced 1.900 g of CO2 and 1.070 g of H2O. What is the empirical formula of the compound?

A 22.5- g sample of ammonium carbonate contains mol of ammonium ions.

How many grams of hydrogen are in 46 g of CH4O?

A compound that is composed of carbon, hydrogen, and oxygen contains 70.6% C, 5.9% H, and 23.5% O by mass. The molecular weight of the compound is 136 amu. What is the molecular formula?

GeF3H is formed from GeH4 and GeF4 in the combination reaction: If the reaction yield is 92.6%, how many moles of GeF4 are needed to produce 8.00 mol of GeF3H?

What is the empirical formula of a compound that contains 29% Na, 41% S, and 30% O by mass?

When the following equation is balanced, the coefficient of nitric acid is .

When the following equation is balanced, the coefficient of H₂is _ .

When the following equation is balanced, the coefficient of Al₂O₃is _ .

There are molecules of methane in 0.123 mol of methane (CH₄) .

A sample of C₃H₈O that contains 200 molecules contains _ carbon atoms.

What is the coefficient of O₂when the following equation is completed and balanced? C₄H₈O₂+ O₂-

There are _ sulfur atoms in 25 molecules of C₄H₄S₂.

What is the maximum mass in grams of NH₃that can be produced by the reaction of 1.0 g of N₂ with 3.0 g of H₂via the equation below?

Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: In a particular experiment, the reaction of 2.5 g of Al with 2.5 g of O₂produced 3.5 g of Al₂O₃. The % yield of the reaction is .

Sulfur and oxygen react in a combination reaction to produce sulfur trioxide, an environmental pollutant: In a particular experiment, the reaction of 1.0 g S with 1.0 g O₂produced 0.80 g of SO₃. The % yield in this experiment is .

Pentacarbonyliron (Fe(CO) ₅) reacts with phosphorous trifluoride (PF₃) and hydrogen, releasing carbon monoxide: The reaction of 5.0 mol of Fe(CO) ₅, 8.0 mol of PF₃and 6.0 mol of H₂will release _ _ mol of CO.

The combustion of propane (C₃H₈) produces CO₂and H₂O: The reaction of 2.5 mol of O₂will produce mol of H₂O.

Combustion of a 0.9835- g sample of a compound containing only carbon, hydrogen, and oxygen produced 1.900 g of CO₂and 1.070 g of H₂O. What is the empirical formula of the compound?

How many grams of hydrogen are in 46 g of CH₄O?

GeF₃H is formed from GeH₄and GeF₄in the combination reaction: If the reaction yield is 92.6%, how many moles of GeF₄are needed to produce 8.00 mol of GeF₃H?