CHM 1045 Spring 2009
Quiz 5
Name (print)___________________
Show your work for complete (and partial) credit. Report your answers to the correct
number of significant figures, and use units where appropriate. All chemical equations
should balance; indicate phases. NA=6.022x1023
1. a) What is the mass of one (average) sodium atom in amu?
b) What is the mass of one (average) sodium atom in grams?
The following information applies to the next three problems.
Compound: MgCl2Mg(NO3)2AgCl AgNO3
f.w.(g/mol): 95.211 148.435 143.321 169.87
MgCl2(aq) + 2AgNO3(aq) → 2AgCl(s) + Mg(NO3)2(aq)
2. How much does 0.055mol of magnesium chloride weigh?
3. How many mols of AgNO3 are required to form 0.275mol of AgCl?
4. What mass of MgCl2 is required to form 1.223g of AgCl?
5. In the following reaction, if 15.0g of each reactant is allowed to react, what will be the
theoretical yield of the product, Al2O3 (101.96g/mol), in grams? Note: this is a
limiting reactant problem. 4Al + 3O2 → 2Al2O3.
4 points extra credit: What is the definition of the mole?