Math Skills Review for Chemistry

Convert 25.0 milliliters (mL) to liters (L).

• 0.025 L

• 2.5 L

• 0.25 L

• 250 L

Write the number 0.00034 in scientific notation.

• 3.4 × 10⁴

• 3.4 × 10⁻⁴

• 34 × 10⁻⁴

• 34 × 10⁴

Balance the following equation: _ C₄H₁₀ + _ O₂ → _ CO₂ + _ H₂O

Which of the following represents the correct balanced equation?

• 2 C₄H₁₀ + 13 O₂ → 8 CO₂ + 10 H₂O

• 1 C₄H₁₀ + 5 O₂ → 4 CO₂ + 2 H₂O

• 1 C₄H₁₀ + 6 O₂ → 4 CO₂ + 4 H₂O

• 2 C₄H₁₀ + 8 O₂ → 4 CO₂ + 8 H₂O

You need to prepare 500 mL of a 0.25 M NaCl solution. How many grams of NaCl do you need? (Molar mass of NaCl = 58.44 g/mol)

• 7.32 g

• 14.64 g

• 2.92 g

• 29.2 g

In the reaction: 2 H₂ + O₂ → 2 H₂O If you start with 4 moles of H₂, how many moles of H₂O will be produced?

• 2 moles

• 4 moles

• 6 moles

• 8 moles

If a substance has a mass of 30 g and a volume of 15 mL, what is its density?

• 2 g/mL

• 0.5 g/mL

• 45 g/mL

• 15 g/mL

What is the percent composition of oxygen in H₂O? (Molar mass of H₂O = 18.02 g/mol)

• 11.2%

• 33.3%

• 88.8%

• 15.6%

How many significant figures are in the measurement 0.004560?

• 3

• 4

• 5

• 2

Simplify the following expression: (3.0 × 10²) × (2.0 × 10⁻³)

• 6.0 × 10⁵

• 6.0 × 10⁻¹

• 6.0 × 10⁻¹

• 6.0 × 10⁻¹

If a gas has a volume of 2.5 L at 300 K, what will its volume be at 600 K, assuming pressure is constant? (Use Charles' Law)

• 1.25 L

• 5.0 L

• 3.5 L

• 6.0 L