Test #1 Review

1. Which pair of atoms represents nuclei that have the same number of neutrons?

a. 56Co and 58Co

b. 57Mn and 57Fe

c. 58Ni and 57Fe

d. 58Ni and 57Co

e. 59Ni and 56Fe

2. Which of the following was used to discover the electron?

a. The gold foil experiement

b. Deflection of cathode rays by electric and magnetic fields

c. The oil drop experiment

d. Electrolysis

e. The mass spectrometer

3. Which sample contains the greatest number of nitrogen atoms?

a. 0.20 mol N2O4

b. 0.40 mol N2

c. 40. g NH3

d. 80. g N2O4

4. How many sodium atoms are in 3.49 grams of sodium?

5. What is the empirical formula of a substance that is 30.% nitrogen and 70.% oxygen? What is the molecular formula if the molar mass is 92 g/mol?

6. A reaction between 150.0 mL of 1.20 M barium carbonate and 16.0 grams of sodium hydroxide produces 30.84 grams barium hydroxide and sodium carbonate.

a. What is the limiting reactant?

b. How many moles of excess reactant are left over?

c. What is the theoretical yield of barium hydroxide?

d. What is the percent yield of barium hydroxide?

• Magnesium hydroxide neutralizes hydrochloric acid to form magnesium chloride and water.

• Write a balanced chemical equation.

• How many liters of 1.22 M magnesium hydroxide are needed to neutralize 1.28 L of 0.56 M hydrochloric acid?