1.
A mole ratio can be the ratio of -
Correct Answer
E. All of the above
Explanation
A mole ratio can be the ratio of a reactant to a product, a reactant to another reactant, a product to another product, or a product to a reactant. This is because mole ratios are used to describe the relationship between the amounts of substances involved in a chemical reaction. The ratio can be determined by examining the coefficients in the balanced chemical equation.
2.
How many moles of hydrogen gas are needed to react completely with two moles of nitrogen gas? 3H2 + N2 --> 2NH3
Correct Answer
B. 6 mol
Explanation
In the given balanced chemical equation, it is stated that 3 moles of hydrogen gas react with 1 mole of nitrogen gas to produce 2 moles of ammonia. Therefore, to react completely with 2 moles of nitrogen gas, we would need to double the amount of hydrogen gas, resulting in 6 moles of hydrogen gas.
3.
How much ammonia (NH3) is produced from two moles of nitrogen gas? 3H2 + N2 --> 2NH3
Correct Answer
C. 4 mol
Explanation
The balanced chemical equation shows that 3 moles of hydrogen gas react with 1 mole of nitrogen gas to produce 2 moles of ammonia. Therefore, if we have 2 moles of nitrogen gas, we can calculate the amount of ammonia produced by using the ratio of moles in the equation. By multiplying 2 moles of nitrogen gas by the ratio of 2 moles of ammonia to 1 mole of nitrogen gas, we find that 4 moles of ammonia are produced.
4.
How many moles of oxygen gas are produced from the decomposition of six moles of potassium chloride? 2KClO3 --> 2KCl + 3O2
Correct Answer
A. 9 mol
Explanation
The balanced chemical equation shows that for every 2 moles of potassium chloride (KClO3) decomposed, 3 moles of oxygen gas (O2) are produced. Therefore, if 6 moles of potassium chloride decompose, we can expect to produce 9 moles of oxygen gas.
5.
How many moles of potassium chloride are produced from the decomposition of six moles of potassium chloride? 2KClO3 --> 2KCl + 3O2
Correct Answer
C. 6 mol
Explanation
The balanced chemical equation shows that for every 2 moles of KClO3 that decompose, 2 moles of KCl are produced. Therefore, if 6 moles of KClO3 decompose, it would produce 6 moles of KCl.
6.
Which of the following has the largest mass of carbon per gram?
Correct Answer
D. CH₃CH₂OH
Explanation
CH₃CH₂OH has the largest mass of carbon per gram because it has two carbon atoms in its structure. H₂CO has one carbon atom, CH₃CO₂H has two carbon atoms, and CH₃OH has one carbon atom. Therefore, CH₃CH₂OH has the highest mass of carbon per gram among the given options.
7.
Which of the following statements is true?
Correct Answer
E. All of the above are true.
Explanation
All of the given statements are true. The first statement states that 1 mole of hydrogen atoms is equal to 6.02 x 10^23 hydrogen atoms, which is consistent with Avogadro's number. The second statement states that 1 mole of pennies is equal to 6.02 x 10^23 pennies, which is also consistent with Avogadro's number. The third statement states that 6.02 x 10^23 hydrogen atoms have a mass of 1.008 g, which is the molar mass of hydrogen. The fourth statement states that the formula mass of O2 is 32.00 amu, which is true. Therefore, all of the statements are true.
8.
One atom of an element has a mass of 9.123 x 10⁻²³ g. There is only one isotope of the element. The element is:
Correct Answer
E. Manganese
Explanation
The mass of one atom of an element is given as 9.123 x 10⁻²³ g. This mass corresponds to the atomic mass of manganese, which is approximately 54.94 g/mol. Since there is only one isotope of the element, manganese is the correct answer.
9.
If these fertilizers are priced according to their nitrogen content, which will be the least expensive per 50 lb. bag?
Correct Answer
C. Ammonium nitrate NH₄NO₃
Explanation
Ammonium nitrate NH₄NO₃ will be the least expensive per 50 lb. bag because it has the highest nitrogen content among the given fertilizers. Since the fertilizers are priced according to their nitrogen content, the one with the highest nitrogen content will have a lower price per bag.
10.
Which of the following has the greatest mass?
Correct Answer
C. 200 molecules of O₂
Explanation
Oxygen (O₂) has a molar mass of 32 g/mol, while water (H₂O) has a molar mass of 18 g/mol. Therefore, 200 molecules of O₂ would have a greater mass compared to 200 molecules of water. The molar mass of Fe is 55.85 g/mol, and the molar mass of CH₄ is 16.04 g/mol, so neither of them have a greater mass than O₂.