Unit 2 Exam Review

What is the percentage of nitrogen by mass in calcium nitrate, Ca(NO₃)₂?

• 25%
• 12%

• 73%

• 17.1%

Answer explanation

Answer Explanation

Sodium hydroxide reacts with carbon dioxide to form sodium carbonate and water:

2NaOH (s) + CO₂ (g) ——-> Na₂CO₃ (s) + H2O (l).

How many grams of Na₂CO₃ can be prepared from 2.40 g of NaOH?

• 3.18 g Na₂CO₃

• 0.318 g Na₂CO₃

• 54.03 g Na₂CO₃

• 2.13 g Na₂CO₃

Answer explanation

Answer Explanation

Tags

NGSS.HS-PS1-7

Suppose 24 mol of methanol and 15 mol of oxygen combine in the following combustion

reaction.

2CH₃OH (l) + 3O₂ (g) ———> 2CO₂ (g) + 4H₂O (g)

What is the excess reagent, and how many moles of it remain at the end of the reaction?

• CH₃OH is in excess, 28 moles will be left at the end of the reaction.

• O₂ is in excess, 14 moles will be left at the end of the reaction.

• CH₃OH is in excess, 14 moles will be left at the end of the reaction.

• O₂ is in excess, 28 moles will be left at the end of the reaction.

Answer explanation

Tags

NGSS.HS-PS1-7

If 3.00 g of titanium metal reacts with 6.00 g of chlorine gas (Cl₂) to form 7.7 g of titanium (IV)

chloride in a combination reaction, what is the percent yield of the product?

• 96% yield of TiCl₄

• 69% yield of TiCl₄

• 72% yield of TiCl₄

• 100% yield of TiCl₄

Answer explanation

There are two parts to this question. The first part is to find the theoretical yield by determining which reagent is the limiting reagent. The second part is to find the percent yield.

Tags

NGSS.HS-PS1-7

Determine the empirical formula for the following compounds.

a) Sn = 5.28g and F = 3.37g

b) 87% N and 12.5% H by mass

• a) Sn₂F₄

  b) N₂H₂

• a) SnF₄

  b) NH₂

• a) Sn₈F₄

  b) NH₂

• a) SnF₂

  b) NH

Answer explanation

Tags

NGSS.HS-PS1-1

Write a balanced molecular equation for

the reaction between aqueous solutions of

acetic acid (HC₂H₂O₂) and barium

hydroxide [Ba(OH)₂].

Answer explanation

Tags

NGSS.HS-PS1-7

What is the oxidation number of sulfur in sulphuric acid (H₂SO₄)?

• -4
• +2
• +6
• +8

Answer explanation

Which of the following statements between HClO₄ and HClO₃ is true?

• 1. The oxidation number of chlorine in HClO₄ has been decreased in HClO₃

• 1. The oxidation numbers for all atoms are the same in both molecules

• 1. The oxidation number for chlorine in HClO₄ has increased in HClO₃

Answer explanation

• 0.1 M

• 1 M

• 100 M

• 10 M

Answer explanation

10 kg mass / 100 liter volume = 0.1 M

A 2.50 L solution contains 5.00 g of NaOH, which has a molecular weight of 40.00 g/mol.

What is the molar concentration of sodium hydroxide in the solution?

• 0.0500 M

• 0.500 M

• 0.325 M

• 0.0325 M

Answer explanation