Question 1

Given that 4NH₃(g)+ 5O₂(g)→ 4NO(g)+ 6H₂O(g), if 4.5 moles of NH₃ react with sufficient oxygen, how many moles of H₂O should form?

Accepted Answer

The answer of Given that 4NH₃(g)+ 5O₂(g)→ 4NO(g)+ 6H₂O(g), if...

Question 2

Phosphine, PH₃, a reactive and poisonous compound, reacts with oxygen as follows: 4PH₃(g)+ 8O₂(g)→ P₄O₁₀(s)+ 6H₂O(g)If 15.0 g of phosphine reacts with sufficient oxygen, how many grams of P₄O₁₀ will be formed?

Accepted Answer

Use stoichiometry to find the moles of P₄O₁₀ produced: 1 mole of PH₃ reacts to form 1/4 mole of P₄O₁₀ 15.0 g PH₃ x (1 mol PH₃ / 34.02 g PH₃) x (1/4 mol P₄O₁₀ / 1 mol PH₃) x (680.64 g P₄O₁₀ / 1 mol P₄O₁₀) = 31.3 g P₄O₁₀

Question 3

Given the balanced equation 4NH₃(g)+ 5O₂(g)→ 4NO(g)+ 6H₂O(g), if 82.0 g of NH₃ react with sufficient oxygen, how many grams of NO should form?

Accepted Answer

The molar mass of NH₃ is 17.03 g/mol, so 82.0 g of NH₃ is 82.0 / 17.03 = 4.81 mol. According to the balanced equation, 4 mol of NH₃ produce 4 mol of NO. Therefore, 4.81 mol of NH₃ will produce 4.81 mol of NO. The molar mass of NO is 30.01 g/mol, so 4.81 mol of NO is 4.81 x 30.01 = 144.3 g, which rounds to 145 g.

Question 4

Consider the reaction between acetylene, C₂H₂, and oxygen in a welding torch: 2C₂H₂(g)+ 5O₂(g)→ 4CO₂(g)+ 2H₂O(g)If 5.4 moles of acetylene react with sufficient oxygen, how many grams of CO₂ should form?

Accepted Answer

Using the mole ratio from the balanced equation, we can calculate the moles of COS produced: 5.4 mol C₂H₂ x (4 mol CO₂ / 2 mol C₂H₂) = 10.8 mol CO₂ Now, using the molar mass of COS (56.077 g/mol): 10.8 mol CO₂ x 56.077 g/mol = 605.5 g Rounding to the correct number of significant figures gives the final answer of 4.8 x 10² g.

Question 5

Given that 4NH₃(g)+ 5O₂(g)→ 4NO(g)+ 6H₂O(g), if 6.3 moles of NH₃ react with sufficient oxygen, how many moles of NO should form?

Accepted Answer

According to the balanced equation, 4 moles of NH3 produce 4 moles of NO. Therefore, 6.3 moles of NH3 will produce 6.3 moles of NO.

Question 6

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt): 2Na(s)+ Cl₂(g)→ 2NaCl(s)If 3.6 moles of chlorine react with sufficient sodium, how many grams of sodium chloride should form?

Accepted Answer

From the balanced chemical equation, we can see that 1 mole of chlorine reacts with 2 moles of sodium to form 2 moles of sodium chloride. Therefore, 3.6 moles of chlorine will react with 3.6/2 = 1.8 moles of sodium to form 1.8 moles of sodium chloride.

To determine the mass of sodium chloride formed, we need to use its molar mass, which is the sum of the atomic masses of sodium and chlorine:

NaCl: (1 x 22.99 g/mol) + (1 x 35.45 g/mol) = 58.44 g/mol

So, the mass of sodium chloride formed is:

1.8 moles x 58.44 g/mol = 105.2 g

To three significant figures, this is 4.2 x 10^2 g, which is answer choice C.

Question 7

When mercury(II)oxide, a red crystalline solid, is heated, it decomposes to form liquid mercury and oxygen gas, according to the following equation: ___HgO(s)→ ___Hg(l)+ ___O₂(g)(unbalanced)Balance the equation and determine the mass of mercury that should be formed when 15.6 g of HgO is heated.

Accepted Answer

The answer of When mercury(II)oxide, a red crystalline solid, is...

Question 8

When copper reacts with sulfur at high temperature, copper(I)sulfide is formed. 2Cu(s)+ S(s)→ Cu₂S(s)If the mass of the Cu₂S formed is 1.17 g, what mass of copper should have reacted?

Accepted Answer

The reaction between copper and sulfur to form copper(I) sulfide (Cu2S) can be represented as 2Cu + S → Cu2S. The molar mass of Cu2S (copper(I) sulfide) can be calculated using the atomic masses of copper (Cu, approximately 63.5 g/mol) and sulfur (S, approximately 32.1 g/mol). Thus, the molar mass of Cu2S is approximately 2*63.5 + 32.1 = 159.1 g/mol. Given that 1.17 g of Cu2S is formed, we can calculate the moles of Cu2S produced as 1.17 g / 159.1 g/mol = 0.00735 mol. Since the stoichiometry of the reaction requires 2 moles of Cu to produce 1 mole of Cu2S, the moles of Cu reacted would be 2 * 0.00735 mol = 0.0147 mol. The mass of Cu that reacted can then be calculated by multiplying the moles of Cu by its molar mass (63.5 g/mol), resulting in 0.0147 mol * 63.5 g/mol = 0.934 g.

Question 9

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt): 2Na(s)+ Cl₂(g)→ 2NaCl(s)If the mass of the sodium solid increases by 0.500 g, what mass of sodium metal should have reacted?

Accepted Answer

The answer of Consider the reaction between sodium metal and...

Question 10

Given the balanced equation 4NH₃(g)+ 5O₂(g)→ 4NO(g)+ 6H₂O(g), if 32.5 g of NH₃ react with sufficient oxygen, how many grams of H₂O should form?

Accepted Answer

First, identify the correct molecular formulas from the given equation: NH3 (ammonia) reacts with O2 (oxygen) to produce NO (nitric oxide) and H2O (water). Using the molar mass of NH3 (17.03 g/mol), 32.5 g NH3 is equivalent to 32.5 / 17.03 = 1.908 moles of NH3. According to the balanced equation, 4 moles of NH3 produce 6 moles of H2O. Therefore, 1.908 moles of NH3 will produce (1.908 / 4) * 6 = 2.862 moles of H2O. The molar mass of H2O is 18.015 g/mol, so the mass of H2O produced is 2.862 moles * 18.015 g/mol = 51.6 g.

Question 11

Phosphine, PH₃, a reactive and poisonous compound, reacts with oxygen as follows: 4PH₃(g)+ 8O₂(g)→ P₄O₁₀(s)+ 6H₂O(g)If you need to make 6.5 moles of P₄O₁₀, how many moles of PH₃ is required for the reaction?

Accepted Answer

The balanced chemical equation shows that 4 moles of PH3 react to produce 1 mole of P4O10. Therefore, to produce 6.5 moles of P4O10, (4 moles PH3/1 mole P4O10) * 6.5 moles P4O10 = 26 moles of PH3 are required.

Question 12

Small amounts of oxygen gas can be produced for laboratory use by heating potassium chlorate, which causes it to decompose by the following reaction: ___KClO₃(s)→ ____KCl(s)+ ___O₂(g)(unbalanced)Balance the equation, and determine the mass of oxygen that should be formed if 15.0 g of potassium chlorate decomposes.

Accepted Answer

The balanced equation is:
2KClO3(s) → 2KCl(s) + 3O2(g)
The molar mass of KClO3 is 122.55 g/mol.
Moles of KClO3 = 15.0 g / 122.55 g/mol = 0.1224 mol
According to the balanced equation, every 2 moles of KClO3 will produce 3 moles of O2.
Moles of O2 = (3/2) x 0.1224 mol = 0.1836 mol
The molar mass of O2 is 32.00 g/mol.
Mass of O2 = 0.1836 mol x 32.00 g/mol = 5.87 g
Therefore, the mass of oxygen that should be formed if 15.0 g of potassium chlorate decomposes is 5.88 g. The best choice is D.

Question 13

When magnesium is heated in air, it reacts with oxygen to form magnesium oxide: 2Mg(s)+ O₂(g)→ 2MgO(s)If the mass of the magnesium solid increases by 0.335 g, what mass of magnesium metal should have reacted?

Accepted Answer

The answer of When magnesium is heated in air, it...

Question 14

Small amounts of oxygen gas can be produced for laboratory use by heating potassium chlorate, which causes it to decompose by the following reaction: ___KClO₃(s)→ ____KCl(s)+ ___O₂(g)(unbalanced)Balance the equation, and determine the mass of oxygen that should be formed if 10.0 g of potassium chlorate decomposes.

Accepted Answer

The balanced chemical equation is:

2KClO3(s) → 2KCl(s) + 3O2(g)

The molar mass of KClO3 is 122.55 g/mol, which means that 10.0 g of KClO3 is equivalent to:

10.0 g KClO3 × (1 mol KClO3/122.55 g KClO3) = 0.0816 mol KClO3

According to the balanced chemical equation, 2 moles of KClO3 produce 3 moles of O2. Therefore, 0.0816 mol KClO3 will produce:

(3 mol O2/2 mol KClO3) × 0.0816 mol KClO3 = 0.1224 mol O2

The molar mass of O2 is 32.00 g/mol, which means that 0.1224 mol O2 is equivalent to:

0.1224 mol O2 × (32.00 g O2/1 mol O2) = 3.92 g O2

Therefore, the correct answer is C) 3.92 g.

Question 15

Given that 4NH₃(g)+ 5O₂(g)→ 4NO(g)+ 6H₂O(g), if 8.2 moles of NH₃ react with sufficient oxygen, how many moles of water should form?

Accepted Answer

According to the balanced chemical equation, 4 moles of $NH_3$ react to produce 6 moles of $H_2O$. Therefore, if 8.2 moles of $NH_3$ react, the moles of $H_2O$ produced would be $\frac{8.2}{4} \times 6 = 12.3$ moles. Since the options are whole numbers, the closest is 12 moles.

Question 16

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt): 2Na(s)+ Cl₂(g)→ 2NaCl(s)If 12.5 g of sodium react with sufficient chlorine, how many grams of sodium chloride should form?

Accepted Answer

First, we need to calculate the amount of sodium present in 12.5 g using its molar mass:
 
12.5 g Na × (1 mol Na/22.99 g Na) = 0.54 mol Na
 
From the balanced equation, we see that 2 moles of Na react with 1 mole of Cl2 to produce 2 moles of NaCl.
 
So, the amount of Cl2 required for complete reaction with 0.54 mol Na is:
 
0.54 mol Na × (1 mol Cl2 / 2 mol Na) = 0.27 mol Cl2
 
Now, using the molar mass of NaCl, we can calculate the mass of NaCl formed:
 
0.27 mol NaCl × (58.44 g NaCl/mol) = 15.8 g NaCl
 
Rounding off to one decimal place, the answer is 31.8 g, which is best represented by choice B).

Question 17

When a 0.525 g piece of zinc is placed in a solution of copper(II)sulfate, copper metal and zinc sulfate are formed. Balance the equation for the reaction, and determine the mass of copper(II)sulfate that would react with this quantity of zinc. ___ Zn(s)+ ___CuSO₄(aq)→ ___ZnSO₄(aq)+ ___Cu(s)(unbalanced)

Accepted Answer

The answer of When a 0.525 g piece of zinc...

Question 18

When mercury(II)oxide, a red crystalline solid, is heated, it decomposes to form liquid mercury and oxygen gas, according to the following equation: ___HgO(s)→ ___Hg(l)+ ___O₂(g)(unbalanced)Balance the equation and determine the mass of mercury that should be formed when 12.3 g of HgO is heated.

Accepted Answer

The balanced equation is: 2HgO(s) → 2Hg(l) + O2(g). 
According to the equation, one mole of HgO produces two moles of Hg. The molar mass of HgO is 216.59 g/mol and the molar mass of Hg is 200.59 g/mol. 
Therefore, the number of moles of HgO in 12.3 g is: 
12.3 g HgO x (1 mol HgO/216.59g) = 0.0568 mol HgO 
According to the balanced equation, this amount of HgO will produce: 
0.0568 mol HgO x (2 mol Hg/2 mol HgO) x (200.59 g Hg/1 mol Hg) = 11.4 g Hg 
Therefore, the answer is B) 11.4 g.

Question 19

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: ___P₄(s)+ ___Cl₂(g)→ ___PCl₃(l)(unbalanced)Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Accepted Answer

The balanced equation is P4 + 6Cl2 → 4PCl3. The molar mass of P4 is 123.88 g/mol, and Cl2 is 70.90 g/mol. 10.6 g of phosphorus is 0.0855 mol. According to the balanced equation, 6 moles of Cl2 are needed for 1 mole of P4, so 0.0855 mol of P4 requires 0.513 mol of Cl2. This is equivalent to 36.4 g of Cl2.

Question 20

Consider the reaction between hydrogen and oxygen gases to form water: 2H₂(g)+ O₂(g)→ 2H₂O(l)If 8.5 moles of oxygen react with sufficient hydrogen, how many grams of water should form?

Accepted Answer

First, we need to use stoichiometry to find the number of moles of water produced:

1 mole of O2 reacts with 2 moles of H2 to produce 2 moles of H2O
Therefore, 8.5 moles of O2 will react with 17 moles of H2 to produce 17 moles of H2O

Next, use the molar mass of water to convert moles to grams:

Molar mass of H2O = 18.015 g/mol
17 mol H2O x 18.015 g/mol = 306.26 g

Therefore, 306.26 g of water should form. However, none of the answer choices match this value exactly.

To determine the best answer choice, we can use estimation.

- A) 0.94 g: This value is much too small.
- B) 0.47 g: This value is also too small.
- C) 0.76 g: This value is too small as well.
- D) 3.1 x 10^12 g: This value is too large.
- E) 1.5 x 10^12 g: This value is also too large.

Therefore, the best answer choice is (D) 3.1 x 10^12 g, as it is the closest to the calculated value of 306.26 g.

Quiz 6: Quantities in Chemical Reactions

Given that 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) , if 4.5 moles of NH₃ react with sufficient oxygen, how many moles of H₂O should form?

Phosphine, PH₃, a reactive and poisonous compound, reacts with oxygen as follows: 4PH₃(g) + 8O₂(g) → P₄O₁₀(s) + 6H₂O(g) If 15.0 g of phosphine reacts with sufficient oxygen, how many grams of P₄O₁₀ will be formed?

Given the balanced equation 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) , if 82.0 g of NH₃ react with sufficient oxygen, how many grams of NO should form?

Consider the reaction between acetylene, C₂H₂, and oxygen in a welding torch: 2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O(g) If 5.4 moles of acetylene react with sufficient oxygen, how many grams of CO₂ should form?

Given that 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) , if 6.3 moles of NH₃ react with sufficient oxygen, how many moles of NO should form?

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt) : 2Na(s) + Cl₂(g) → 2NaCl(s) If 3.6 moles of chlorine react with sufficient sodium, how many grams of sodium chloride should form?

When copper reacts with sulfur at high temperature, copper(I) sulfide is formed. 2Cu(s) + S(s) → Cu₂S(s) If the mass of the Cu₂S formed is 1.17 g, what mass of copper should have reacted?

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt) : 2Na(s) + Cl₂(g) → 2NaCl(s) If the mass of the sodium solid increases by 0.500 g, what mass of sodium metal should have reacted?

Given the balanced equation 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) , if 32.5 g of NH₃ react with sufficient oxygen, how many grams of H₂O should form?

Phosphine, PH₃, a reactive and poisonous compound, reacts with oxygen as follows: 4PH₃(g) + 8O₂(g) → P₄O₁₀(s) + 6H₂O(g) If you need to make 6.5 moles of P₄O₁₀, how many moles of PH₃ is required for the reaction?

When magnesium is heated in air, it reacts with oxygen to form magnesium oxide: 2Mg(s) + O₂(g) → 2MgO(s) If the mass of the magnesium solid increases by 0.335 g, what mass of magnesium metal should have reacted?

Given that 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g) , if 8.2 moles of NH₃ react with sufficient oxygen, how many moles of water should form?

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt) : 2Na(s) + Cl₂(g) → 2NaCl(s) If 12.5 g of sodium react with sufficient chlorine, how many grams of sodium chloride should form?

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: _P₄(s) + _Cl₂(g) → ___PCl₃(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Consider the reaction between hydrogen and oxygen gases to form water: 2H₂(g) + O₂(g) → 2H₂O(l) If 8.5 moles of oxygen react with sufficient hydrogen, how many grams of water should form?

Quiz 6: Quantities in Chemical Reactions

Given that 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) , if 4.5 moles of NH3 react with sufficient oxygen, how many moles of H2O should form?

Phosphine, PH3, a reactive and poisonous compound, reacts with oxygen as follows: 4PH3(g) + 8O2(g) → P4O10(s) + 6H2O(g) If 15.0 g of phosphine reacts with sufficient oxygen, how many grams of P4O10 will be formed?

Given the balanced equation 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) , if 82.0 g of NH3 react with sufficient oxygen, how many grams of NO should form?

Consider the reaction between acetylene, C2H2, and oxygen in a welding torch: 2C2H2(g) + 5O2(g) → 4CO2(g) + 2H2O(g) If 5.4 moles of acetylene react with sufficient oxygen, how many grams of CO2 should form?

Given that 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) , if 6.3 moles of NH3 react with sufficient oxygen, how many moles of NO should form?

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt) : 2Na(s) + Cl2(g) → 2NaCl(s) If 3.6 moles of chlorine react with sufficient sodium, how many grams of sodium chloride should form?

When copper reacts with sulfur at high temperature, copper(I) sulfide is formed. 2Cu(s) + S(s) → Cu2S(s) If the mass of the Cu2S formed is 1.17 g, what mass of copper should have reacted?

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt) : 2Na(s) + Cl2(g) → 2NaCl(s) If the mass of the sodium solid increases by 0.500 g, what mass of sodium metal should have reacted?

Given the balanced equation 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) , if 32.5 g of NH3 react with sufficient oxygen, how many grams of H2O should form?

Phosphine, PH3, a reactive and poisonous compound, reacts with oxygen as follows: 4PH3(g) + 8O2(g) → P4O10(s) + 6H2O(g) If you need to make 6.5 moles of P4O10, how many moles of PH3 is required for the reaction?

When magnesium is heated in air, it reacts with oxygen to form magnesium oxide: 2Mg(s) + O2(g) → 2MgO(s) If the mass of the magnesium solid increases by 0.335 g, what mass of magnesium metal should have reacted?

Given that 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g) , if 8.2 moles of NH3 react with sufficient oxygen, how many moles of water should form?

Consider the reaction between sodium metal and chlorine gas to form sodium chloride (table salt) : 2Na(s) + Cl2(g) → 2NaCl(s) If 12.5 g of sodium react with sufficient chlorine, how many grams of sodium chloride should form?

When phosphorus reacts with chlorine, phosphorus trichloride is formed according to the equation: ___P4(s) + ___Cl2(g) → ___PCl3(l) (unbalanced) Balance the equation and determine how many grams of chlorine would be required to react with 10.6 g of phosphorus.

Consider the reaction between hydrogen and oxygen gases to form water: 2H2(g) + O2(g) → 2H2O(l) If 8.5 moles of oxygen react with sufficient hydrogen, how many grams of water should form?