Chemistry Unit 1 Practice Problems - AP Classroom

Density and Volume Calculations

• Mercury (Hg) has a density of approximately 14 g/mL at 0°C.
• To find the volume of one mole of Hg at this temperature, use the formula:
  • Volume = Mass / Density
• The molar mass of mercury is about 200.59 g.
• Calculating with density:
  • Volume = 200.59 g / 14 g/mL ≈ 14.34 mL
• The closest answer to the calculated volume is 14 mL, making option D the correct choice.

Mole Calculations in Compounds

• A student compares 1g samples of NaCl, KBr, and KCl.
• Molar masses relevant for calculations:
  • NaCl: 58.44 g/mol
  • KBr: 119.00 g/mol
  • KCl: 74.55 g/mol
• To determine the number of moles, use:
  • Moles = Mass / Molar Mass
• Calculating moles for each:
  • NaCl: 1 g / 58.44 g/mol ≈ 0.0171 moles
  • KBr: 1 g / 119 g/mol ≈ 0.0084 moles
  • KCl: 1 g / 74.55 g/mol ≈ 0.0134 moles
• Order of increasing moles: KBr < KCl < NaCl.

Test your knowledge with practice problems from Chemistry Unit 1, designed specifically for AP Classroom. This quiz covers topics such as density calculations and mole conversions for various compounds. Challenge yourself and assess your understanding of these fundamental concepts!