Summary Week 3 Assignment worksheet

Week 3 Assignment: 15 points

1. Balance these chemical reactions: (2 point each, 8 points total)


2NaBr + CaF2 → 2NaF + CaBr2



2HCl + CaCO3 → CaCl2 + H2O + CO2



FeCl3 + 3NaOH → Fe(OH)3 + 3NaCl



CaCO3 + H2SO4 → CaSO4 + CO2 + H2O

Unless I’m wrong, the last equation is already balanced.



2. Calculate the formula mass of Al2(SO4)3. (2 points)
a. Answer : 342.151 amu or g/mol
b. Work : (weight of 1 Al atom x 2) + (weight of 1 S atom x 3) + (weight of 1 O atom x 12)
53.9631 + 96.195+191.9928
342.151 amu

3. Calculate the mass of 2.5 moles of NaOH. (1 points)
a. Answer : 99.75 g/mol
b. Work : 1 mole NaOH = 39.9 g/mol
Because (Na = 22.989 g/mol) and (O =15.999 g/mol) and (H = 10079 g/mol)
39.9
39.9 x 2.5
99.75

4. For the balanced chemical equation:

2 K + 1 MgBr2 → 2 KBr + 1 Mg

Answer the following questions:


a. If you produce 7 mols of KBr, how many mols of MgBr 2 did you need? (1 point)
a. Answer : 3.5 mols
b. Work : 7 molK Br x 1 molMgBr molKBr = 3.5 molMgBr2