AP Chemistry - Week 1 Homework: Moles and Atomic Mass
Unit 1: Atomic Structure and Properties

Learning Objectives:
1. Calculate quantities of a substance using dimensional analysis and the mole concept
2. Explain the quantitative relationship between mass and moles
3. Use Avogadro's number in calculations

Problems:

Problem 1: Basic Mole Calculations
a) How many moles are in 25.0 g of carbon dioxide (CO2)?
b) What is the mass of 2.50 moles of sodium chloride (NaCl)?
c) How many molecules are in 0.750 moles of water (H2O)?
d) Calculate the number of atoms in 15.0 g of aluminum.

Problem 2: Molar Mass Calculations
a) Calculate the molar mass of Ca(NO3)2
b) Calculate the molar mass of C6H12O6 (glucose)
c) How many moles are in 100.0 g of CaCO3?
d) What mass of H2SO4 contains 3.50 moles?

Problem 3: Avogadro's Number Applications
a) How many atoms are in 2.5 moles of iron?
b) How many molecules are in 0.25 moles of CO2?
c) How many moles contain 1.5 × 10^24 atoms of carbon?
d) Calculate the mass of one molecule of water in grams.

Problem 4: Percent Composition
For calcium carbonate (CaCO3):
a) Calculate the percent composition by mass of each element
b) How many grams of calcium are in 50.0 g of CaCO3?
c) What mass of CaCO3 contains 12.0 g of carbon?

Problem 5: Empirical Formulas
A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass.
a) Determine the empirical formula
b) Show all calculation steps
c) If the molar mass is 180.0 g/mol, what is the molecular formula?

Due Date: End of Week 1