Spring 2002
HOMEWORK #1 
Due on Thursday, February 7 (L2) or February 8 (L3), 2002
Chemistry 1201

YOUR NAME (circle it if it is OK to leave your paper outside 640 Choppin)                                                    .
Chemistry 1201 Lecture Section      2   or      3. 
In questions 2-7 show ALL your work for full marks. Staple your work to this answer sheet and hand it to me in class. You can work together with other students, but each of you is responsible for handing in a separate set of solutions. In addition, please quote answers in boxes.
   Q1: Will you be willing to print future homework forms from the web? a)     YES    b)  NO
Value
5 		 Q2: An element has 2 naturally occurring isotopes with the following masses and  abundance: 
Isotope 1: 6.0151 amu,  7.50%         Isotope 2: 7.0160  amu,  92.50%
What is the average atomic mass of this element (in amu)? 		 Answer: 
5 Q3: How many picometers are there in 1 x 10-2 kilometers? Answer:
10 Q4: A compound contains 40.0% C, 6.7% H, and 53.3% O. Its molar mass is 60.06 g/mol.  What is the empirical formula of the compound? Answer:
10
 
 
 

 

 Q5: Sodium silicate reacts with hydrofluoric acid in the following way:
Na2SiO3(s) + 8HF(aq) --> H2SiF6(aq) + 2NaF(aq) + 3H2O(l)
a) How many moles of HF are required to dissolve 0.50 mol of Na2SiO3 ? 

b) How many grams of NaF can be theoretically produced from 0.50 mol of Na2SiO3 ? 

 Answer to a):
 

Answer to b):
10
 
 

 

 Q6: Consider the following reaction: 4NH3(g) + 5O2(g) --> 4NO(g) + 6H2O(g).
In a certain experiment 2.50 g of NH3 reacts with 2.85 g of O2.
a) Which reactant is the limiting reactant? 

b) How many grams of NO form? 

c) How many moles of the excess reactant remain after the reaction? 

 Answer to a):
 

Answer to b):
 

Answer to c):
10 Q7: How many grams of CO2 can form when a mixture of 4.95 g C2H4 and 3.25 g of oxygen  is ignited. Assume complete combustion to carbon dioxide and steam. Answer: