Semester Review

Which conversion factor should be used to solve the following, "How many moles are in 28 grams of CO₂?"

• 1 mol = 22.4 L

• 1 mol = 6.02x10²³ atoms

• 1 mol = 44.01 g

• more than one

What is the molar mass of Hydrogen Peroxide (H₂O₂)?

• 48.10 g/mol

• 36.54 g/mol

• 34.02 g/mol

• 35.51 g/mol

What is the percent by mass of sodium in NaCl?

• 39%

• 35%

• 61%

• 65%

What is the percent composition of S in the formula (NH₄)₂S ?

• 12.05%

• 47.11%

• 19.30%

• 56.18%

When you make a dilution, which of these values remains constant?

• The molarity (M)

• The volume (V)

• The total moles of solute

• The concentration

How many mL of 1.0M KBr solution would you need to prepare 250 mL of a 0.2M dilution?

• 175 mL

• 50 mL

• 250 mL

• 5 mL