Question 1

A compound that is composed of only carbon and hydrogen contains 80.0% C and 20.0% H by mass. What is the empirical formula of the compound? A)C₂₀H₆₀ B)C₇H₂₀ C)C H₃ D)C₂H₆ E)CH₄

Accepted Answer

To find the empirical formula, we need to determine the ratio of atoms present in the compound. We can assume a 100g sample of the compound, which means 80g is carbon and 20g is hydrogen.

Then, we can convert the mass to moles using the atomic weights:
- 80g C = 6.67 moles C
- 20g H = 19.76 moles H

Next, we find the simplest whole number ratio by dividing both by the smallest mole value (in this case, 6.67 moles C):

- 6.67 moles C / 6.67 = 1.00 mol C
- 19.76 moles H / 6.67 = 2.96 mol H

Thus, the empirical formula is CH1.00, which we can round to simply CH.

The other answer choices have different ratios of carbon to hydrogen and do not match the given percentages.

Question 2

Lead (II)carbonate decomposes to give lead (II)oxide and carbon dioxide: PbCO₃ (s)→ PbO (s)+ CO₂ (g) How many grams of lead (II)oxide will be produced by the decomposition of 2.50 g of lead (II)carbonate? A)0.41 B)2.50 C)0.00936 D)2.09 E)2.61

Accepted Answer

First, we need to balance the chemical equation, but it seems already balanced: PbCO3 (s) → PbO (s) + CO2 (g). Next, we calculate the molar mass of lead (II) carbonate (PbCO3) which is 207.2 (Pb) + 12.01 (C) + 3*16.00 (O3) = 267.21 g/mol. The molar mass of lead (II) oxide (PbO) is 207.2 (Pb) + 16.00 (O) = 223.2 g/mol. Given 2.50 g of PbCO3, we find the moles of PbCO3: 2.50 g / 267.21 g/mol = 0.00936 mol. Since the reaction is a 1:1 ratio, the moles of PbO produced will also be 0.00936 mol. To find the mass of PbO produced: 0.00936 mol * 223.2 g/mol = 2.09 g.

Question 3

What is the empirical formula of a compound that contains 49.4% K, 20.3% S, and 30.3% O by mass? A)KSO₂ B)KSO₃ C)K₂SO₄ D)K₂O₃ E)KSO₄

Accepted Answer

The answer of What is the empirical formula of a...

Question 4

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)C₈H₄O C)C₄H₄O D)C₉H₁₂O E)C₅H₆O₂

Accepted Answer

The answer of A compound that is composed of carbon,...

Question 5

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g)+ 3 H₂ (g)→ 2NH₃ (g) If the reaction yield is 87.5%, how many moles of N₂ are needed to produce 3.00 mol of NH₃?. A)0.166 B)1.00 C)1.5 D)1.71 E)2.32

Accepted Answer

The answer of Under appropriate conditions, nitrogen and hydrogen undergo...

Question 6

The combustion of ammonia in the presence of excess oxygen yields NO₂ and H₂O: 4 NH₃ (g)+ 7 O₂ (g)→ 4 NO₂ (g)+ 6 H₂O (g) The combustion of 43.9 g of ammonia produces __________ g of NO₂. A)2.58 B)178 C)119 D)0.954 E)43.9

Accepted Answer

1) Convert the mass of ammonia to moles:

43.9 g NH3 x (1 mol NH3/17.03 g NH3) = 2.58 mol NH3

2) Use the balanced equation to determine the moles of N2O produced:

From the balanced equation, the mole ratio of NH3:N2O is 4:4 (or 1:1)
Therefore, 2.58 mol N2O will be produced.

3) Convert moles of N2O to grams:

2.58 mol N2O x (44.01 g N2O/1 mol N2O) = 113.88 g N2O

Rounding to the correct number of significant figures gives us a final answer of 119 g N2O. Therefore, the correct answer is (C).

Question 7

The combustion of propane (C₃H₈)in the presence of excess oxygen yields CO₂ and H₂O: C₃H₈ (g)+ 5 O₂ (g)→ 3CO₂ (g)+ 4 H₂O (g) When 2.5 mol of O₂ are consumed in their reaction, __________ mol of CO₂ are produced. A)1.5 B)3.0 C)5.0 D)6.0 E)2.5

Accepted Answer

The answer of The combustion of propane (C₃H₈)in the presence...

Question 8

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)C₂ H₅O B)C₄ H₁₀O₂ C)C₄ H₁₁O₂ D)C₄ H₁₀O E)C₂ H₅O₂

Accepted Answer

First, we need to find the moles of each product using their molar masses: 
moles of COS: 1.900 g / 60.07 g/mol = 0.03163 mol 
moles of H2O: 1.070 g / 18.02 g/mol = 0.05935 mol

Next, we need to find the moles of carbon, hydrogen, and oxygen in the original sample: 
moles of carbon = moles of COS = 0.03163 mol 
moles of hydrogen = 2 x moles of H2O = 0.1187 mol 
moles of oxygen = (moles of COS1U1B12S1U1B0 x 2) + (moles of H2O x 1) - moles of sample 
moles of oxygen = (0.03163 x 2) + (0.05935 x 1) - (0.9835 / 44.01) = 0.03947 mol

Finally, we need to find the empirical formula by dividing each mole value by the smallest mole value: 
empirical formula = C1.41H4.99O1 
We can round to the nearest whole number to get the final answer of: 
empirical formula = C1U1B14S1U1B0 H5O

Question 9

Combustion of a 1.031-g sample of a compound containing only carbon, hydrogen, and oxygen produced 2.265 g of CO₂ and 1.236 g of H₂O. What is the empirical formula of the compound? A)C₃H₈O B)C₃H₅O C)C₆H₁₆O₂ D)C₃H₉O₃ E)C₃H₆O₃

Accepted Answer

The answer of Combustion of a 1.031-g sample of a...

Question 10

A compound that is composed of only carbon and hydrogen contains 85.7% C and 14.3% H by mass. What is the empirical formula of the compound? A)CH₂ B)C₂H₄ C)C H4₂ D)C₄H₈ E)C₈₆H₁₄

Accepted Answer

The empirical formula is determined by the simplest whole number ratio of moles of each element. For 85.7% C and 14.3% H, the ratio is approximately 1:2, giving CH₂.

Question 11

The combustion of propane (C₃H₈)produces CO₂ and H₂O: C₃H₈ (g)+ 5 O₂ (g)→ 3CO₂ (g)+ 4 H₂O (g) The reaction of 2.5 mol of O₂ with 4.6 mol of C₃H₈ will produce __________ mol of H₂O. A)4.0 B)3.0 C)2.5 D)2.0 E)1.0

Accepted Answer

From the balanced equation, it can be seen that 5 moles of O₂ are required to react with 1 mole of C₃H₈. Therefore, to react with 4.6 mol of C₃H₈, we need (5/1) x 4.6 = 23 mol of O₂. However, we only have 2.5 mol of O₂, which is limiting. Therefore, the amount of H₂O produced will be determined by the amount of O₂ we have, and we can use the stoichiometric ratio to find it: 2.5 mol O₂ x (4/5) x (4/3) = 2.0 mol H₂O Therefore, the answer is D, 2.0.

Question 12

A compound contains 38.7% K, 13.9% N, and 47.4% O by mass. What is the empirical formula of the compound? A)KNO₃ B)K₂N₂O₃ C)KNO₂ D)K₂NO₃ E)K₄NO₅

Accepted Answer

To find the empirical formula, divide the percent by the atomic mass of each element to find the mole ratio: K (38.7%/39.1 = 0.99), N (13.9%/14.0 = 0.99), O (47.4%/16.0 = 2.96). Simplifying the ratios to whole numbers gives KNO3.

Question 13

A compound contains 40.0% C, 6.71% H, and 53.29% O by mass. The molecular weight of the compound is 60.05 amu. The molecular formula of this compound is __________. A)C₂H₄O₂ B)C H₂O C)C₂H₃O₄ D)C₂H₂O₄ E)CHO₂

Accepted Answer

The answer of A compound contains 40.0% C, 6.71% H,...

Question 14

GeF₃H is formed from GeH₄ and GeF₄ in the combination reaction: GeH₄ + 3Ge F₄ → 4GeF₃H If the reaction yield is 92.6%, how many moles of GeF₄ are needed to produce 8.00 mol of GeF₃H? A)3.24 B)5.56 C)6.48 D)2.78 E)2.16

Accepted Answer

First, we need to determine the theoretical yield of GeF₃H using stoichiometry. From the balanced equation, we can see that for every 3 moles of GeF₄, we get 4 moles of GeF₃H. Therefore, to produce 8.00 mol of GeF₃H, we need: (8.00 mol GeF₃H) x (3 mol GeF₄/4 mol GeF₃H) = 6.00 mol GeF₄ Next, we can use the reaction yield of 92.6% to determine how much GeF₄ we need in reality: (actual yield) = (reaction yield) x (theoretical yield) (actual yield) = (0.926) x (6.00 mol) (actual yield) = 5.56 mol Therefore, the answer is choice C) 6.48, since we need 5.56 mol of GeF₄ to produce 8.00 mol of GeF₃H.

Question 15

Calcium carbide (CaC₂)reacts with water to produce acetylene (C₂H₂): CaC₂ (s)+ 2 H₂O (g)→ Ca(OH)₂ (s)+ C₂H₂ (g) Production of 13 g of C₂H₂ requires consumption of __________ g of H₂O. A)4.5 B)9.0 C)18 D)4.8 × 10² E)4.8 × 10^-2

Accepted Answer

The answer of Calcium carbide (CaC₂)reacts with water to produce...

Question 16

What is the empirical formula of a compound that contains 29% Na, 41% S, and 30% O by mass? A)Na₂S₂O₃ B)NaSO₂ C)NaSO D)NaSO3₄ E)Na₂S₂O₆

Accepted Answer

The empirical formula is determined by converting the percentage of each element to moles and finding the simplest whole number ratio. For Na: 29g/23g/mol = 1.26 mol, for S: 41g/32g/mol = 1.28 mol, for O: 30g/16g/mol = 1.88 mol. The simplest ratio is approximately 2:2:3, giving Na2S2O3.

Question 17

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g)+ 3 H₂ (g)→ 2NH₃ (g) A 7.1-g sample of N₂ requires __________ g of H₂ for complete reaction. A)0.51 B)0.76 C)1.2 D)1.5 E)17.2

Accepted Answer

The answer of Under appropriate conditions, nitrogen and hydrogen undergo...

Question 18

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g)+ 3 H₂ (g)→ 2NH₃ (g) A __________ g sample of N₂ requires 3.0 g of H₂ for complete reaction. A)0.51 B)0.76 C)1.2 D)14.0 E)17.2

Accepted Answer

The answer of Under appropriate conditions, nitrogen and hydrogen undergo...

Question 19

Calcium carbide (CaC₂)reacts with water to produce acetylene (C₂H₂): CaC₂ (s)+ 2 H₂O (g)→ Ca(OH)₂ (s)+ C₂H₂ (g) The complete reaction of 57.4 g of CaC₂ requires consumption of __________ g of H₂O. A)0.895 B)64.1 C)32.3 D)1.79 E)18.0

Accepted Answer

Using stoichiometry and molar masses, we can calculate the amount of H₂O needed to react with 57.4 g of CaC₂: 57.4 g CaC₂ x (1 mol CaC₂/64.1 g CaC₂) x (2 mol H₂O/1 mol CaC₂) x (18.015 g H₂O/1 mol H₂O) = 32.3 g H₂O Therefore, the correct answer is choice C, 32.3 g.

Question 20

A compound is composed of only C, H, and O. The combustion of a 0.519-g sample of the compound yields 1.24 g of CO₂ and 0.255 g of H₂O. What is the empirical formula of the compound? A)C₆H₆O B)C₃H₃O C)CH₃O D)C₂H₆O₅ E)C₂H₆O₂

Accepted Answer

The answer of A compound is composed of only C,...

Quiz 3: Stoichiometry: Calculations With Chemical Formulas and Equations

A compound that is composed of only carbon and hydrogen contains 80.0% C and 20.0% H by mass. What is the empirical formula of the compound?

Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO₃ (s) → PbO (s) + CO₂ (g) How many grams of lead (II) oxide will be produced by the decomposition of 2.50 g of lead (II) carbonate?

What is the empirical formula of a compound that contains 49.4% K, 20.3% S, and 30.3% O by mass?

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?

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g) + 3 H₂ (g) → 2NH₃ (g) If the reaction yield is 87.5%, how many moles of N₂ are needed to produce 3.00 mol of NH₃?.

The combustion of ammonia in the presence of excess oxygen yields NO₂ and H₂O: 4 NH₃ (g) + 7 O₂ (g) → 4 NO₂ (g) + 6 H₂O (g) The combustion of 43.9 g of ammonia produces __________ g of NO₂.

The combustion of propane (C₃H₈) in the presence of excess oxygen yields CO₂ and H₂O: C₃H₈ (g) + 5 O₂ (g) → 3CO₂ (g) + 4 H₂O (g) When 2.5 mol of O₂ are consumed in their reaction, __________ mol of CO₂ are produced.

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?

Combustion of a 1.031-g sample of a compound containing only carbon, hydrogen, and oxygen produced 2.265 g of CO₂ and 1.236 g of H₂O. What is the empirical formula of the compound?

A compound that is composed of only carbon and hydrogen contains 85.7% C and 14.3% H by mass. What is the empirical formula of the compound?

The combustion of propane (C₃H₈) produces CO₂ and H₂O: C₃H₈ (g) + 5 O₂ (g) → 3CO₂ (g) + 4 H₂O (g) The reaction of 2.5 mol of O₂ with 4.6 mol of C₃H₈ will produce __________ mol of H₂O.

A compound contains 38.7% K, 13.9% N, and 47.4% O by mass. What is the empirical formula of the compound?

A compound contains 40.0% C, 6.71% H, and 53.29% O by mass. The molecular weight of the compound is 60.05 amu. The molecular formula of this compound is __________.

GeF₃H is formed from GeH₄ and GeF₄ in the combination reaction: GeH₄ + 3Ge F₄ → 4GeF₃H If the reaction yield is 92.6%, how many moles of GeF₄ are needed to produce 8.00 mol of GeF₃H?

Calcium carbide (CaC₂) reacts with water to produce acetylene (C₂H₂) : CaC₂ (s) + 2 H₂O (g) → Ca(OH) ₂ (s) + C₂H₂ (g) Production of 13 g of C₂H₂ requires consumption of __________ g of H₂O.

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

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g) + 3 H₂ (g) → 2NH₃ (g) A 7.1-g sample of N₂ requires __________ g of H₂ for complete reaction.

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g) + 3 H₂ (g) → 2NH₃ (g) A __________ g sample of N₂ requires 3.0 g of H₂ for complete reaction.

Calcium carbide (CaC₂) reacts with water to produce acetylene (C₂H₂) : CaC₂ (s) + 2 H₂O (g) → Ca(OH) ₂ (s) + C₂H₂ (g) The complete reaction of 57.4 g of CaC₂ requires consumption of __________ g of H₂O.

A compound is composed of only C, H, and O. The combustion of a 0.519-g sample of the compound yields 1.24 g of CO₂ and 0.255 g of H₂O. What is the empirical formula of the compound?

Quiz 3: Stoichiometry: Calculations With Chemical Formulas and Equations

A compound that is composed of only carbon and hydrogen contains 80.0% C and 20.0% H by mass. What is the empirical formula of the compound?

Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO3 (s) → PbO (s) + CO2 (g) How many grams of lead (II) oxide will be produced by the decomposition of 2.50 g of lead (II) carbonate?

What is the empirical formula of a compound that contains 49.4% K, 20.3% S, and 30.3% O by mass?

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?

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N2 (g) + 3 H2 (g) → 2NH3 (g) If the reaction yield is 87.5%, how many moles of N2 are needed to produce 3.00 mol of NH3?.

The combustion of ammonia in the presence of excess oxygen yields NO2 and H2O: 4 NH3 (g) + 7 O2 (g) → 4 NO2 (g) + 6 H2O (g) The combustion of 43.9 g of ammonia produces __________ g of NO2.

The combustion of propane (C3H8) in the presence of excess oxygen yields CO2 and H2O: C3H8 (g) + 5 O2 (g) → 3CO2 (g) + 4 H2O (g) When 2.5 mol of O2 are consumed in their reaction, __________ mol of CO2 are produced.

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?

Combustion of a 1.031-g sample of a compound containing only carbon, hydrogen, and oxygen produced 2.265 g of CO2 and 1.236 g of H2O. What is the empirical formula of the compound?

A compound that is composed of only carbon and hydrogen contains 85.7% C and 14.3% H by mass. What is the empirical formula of the compound?

The combustion of propane (C3H8) produces CO2 and H2O: C3H8 (g) + 5 O2 (g) → 3CO2 (g) + 4 H2O (g) The reaction of 2.5 mol of O2 with 4.6 mol of C3H8 will produce __________ mol of H2O.

A compound contains 38.7% K, 13.9% N, and 47.4% O by mass. What is the empirical formula of the compound?

A compound contains 40.0% C, 6.71% H, and 53.29% O by mass. The molecular weight of the compound is 60.05 amu. The molecular formula of this compound is __________.

GeF3H is formed from GeH4 and GeF4 in the combination reaction: GeH4 + 3Ge F4 → 4GeF3H If the reaction yield is 92.6%, how many moles of GeF4 are needed to produce 8.00 mol of GeF3H?

Calcium carbide (CaC2) reacts with water to produce acetylene (C2H2) : CaC2 (s) + 2 H2O (g) → Ca(OH) 2 (s) + C2H2 (g) Production of 13 g of C2H2 requires consumption of __________ g of H2O.

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

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N2 (g) + 3 H2 (g) → 2NH3 (g) A 7.1-g sample of N2 requires __________ g of H2 for complete reaction.

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N2 (g) + 3 H2 (g) → 2NH3 (g) A __________ g sample of N2 requires 3.0 g of H2 for complete reaction.

Calcium carbide (CaC2) reacts with water to produce acetylene (C2H2) : CaC2 (s) + 2 H2O (g) → Ca(OH) 2 (s) + C2H2 (g) The complete reaction of 57.4 g of CaC2 requires consumption of __________ g of H2O.

A compound is composed of only C, H, and O. The combustion of a 0.519-g sample of the compound yields 1.24 g of CO2 and 0.255 g of H2O. What is the empirical formula of the compound?

Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO₃ (s) → PbO (s) + CO₂ (g) How many grams of lead (II) oxide will be produced by the decomposition of 2.50 g of lead (II) carbonate?

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g) + 3 H₂ (g) → 2NH₃ (g) If the reaction yield is 87.5%, how many moles of N₂ are needed to produce 3.00 mol of NH₃?.

The combustion of ammonia in the presence of excess oxygen yields NO₂ and H₂O: 4 NH₃ (g) + 7 O₂ (g) → 4 NO₂ (g) + 6 H₂O (g) The combustion of 43.9 g of ammonia produces __________ g of NO₂.

The combustion of propane (C₃H₈) in the presence of excess oxygen yields CO₂ and H₂O: C₃H₈ (g) + 5 O₂ (g) → 3CO₂ (g) + 4 H₂O (g) When 2.5 mol of O₂ are consumed in their reaction, __________ mol of CO₂ are produced.

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?

Combustion of a 1.031-g sample of a compound containing only carbon, hydrogen, and oxygen produced 2.265 g of CO₂ and 1.236 g of H₂O. What is the empirical formula of the compound?

The combustion of propane (C₃H₈) produces CO₂ and H₂O: C₃H₈ (g) + 5 O₂ (g) → 3CO₂ (g) + 4 H₂O (g) The reaction of 2.5 mol of O₂ with 4.6 mol of C₃H₈ will produce __________ mol of H₂O.

GeF₃H is formed from GeH₄ and GeF₄ in the combination reaction: GeH₄ + 3Ge F₄ → 4GeF₃H If the reaction yield is 92.6%, how many moles of GeF₄ are needed to produce 8.00 mol of GeF₃H?

Calcium carbide (CaC₂) reacts with water to produce acetylene (C₂H₂) : CaC₂ (s) + 2 H₂O (g) → Ca(OH) ₂ (s) + C₂H₂ (g) Production of 13 g of C₂H₂ requires consumption of __________ g of H₂O.

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g) + 3 H₂ (g) → 2NH₃ (g) A 7.1-g sample of N₂ requires __________ g of H₂ for complete reaction.

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g) + 3 H₂ (g) → 2NH₃ (g) A __________ g sample of N₂ requires 3.0 g of H₂ for complete reaction.

Calcium carbide (CaC₂) reacts with water to produce acetylene (C₂H₂) : CaC₂ (s) + 2 H₂O (g) → Ca(OH) ₂ (s) + C₂H₂ (g) The complete reaction of 57.4 g of CaC₂ requires consumption of __________ g of H₂O.

A compound is composed of only C, H, and O. The combustion of a 0.519-g sample of the compound yields 1.24 g of CO₂ and 0.255 g of H₂O. What is the empirical formula of the compound?