Exam. 1
Dr. Pu
Chem 110, Spring 2006
Name:________________________
Last
First
You must show all work for the problems in the space provided.
Useful information is provided on page1 and the last two pages.
Point Breakdown
Page
Pts
2
24
3
24
4
12
5
20
6
20
total
100
Pts gain
tºF = (9/5) tºC +32
1
Name:_______________________
___1) 19F, 20Ne, and 24Mg2+ all have the same
(a) mass number
(b) atomic number
(c) number of electrons
(d) number of neutrons
____2) When decomposed chemically, 73.0g of a sample of HCl produce 71.0g of Cl2 and 2.0g
of H2, while 34.0g of a sample of H2S produce 32.0g of S and 2.0g of H2. This is an example of
the Law:
(a) of conservation of mass
(b) of multiple proportions
(c) of definite proportions
(d) none of above
______3) Aspirin begins to melt at a temperature of 128°C. Which of the following
temperatures shows the correct temperature on the Kelvin or Fahrenheit scale for the melting
point of aspirin?
(a) 401°F is the melting point of aspirin.
(b) -145 K is the melting point of aspirin.
(c) 173°F is the melting point of aspirin.
(d) 53°F is the melting point of aspirin.
(e) 262°F is the melting point of aspirin.
____4). A chemical change always involves a change in (I) appearance (II) state (III)
composition (IV) temperature
(a) I and II
(b) I, II and IV
(c) III only
(d) II and I
2
Name:_______________________
_____5) An element has two stable isotopes. The mass and percentage of each are
106.90 amu
51.5%
108.90amu
48.5%
The element is which of the following?
(a) Pd
(b) Ag
(c) Cd
(d) In
____6) In which compound does carbon have an oxidation state of zero?
(a) C2H2
(b) CH2O
(c) CH3OH
(d) Na2CO3
(e) CO2
7)12pts. Balance the following equation by inspection
(a) ___Mg3N2(s) + ____H2O(l)  ____Mg(OH)2(s) + ____NH3(g)
(b) ____KO2(s) + ____CO2(g)  ____K2CO3(s) + ____O2(g)
(c) ____H2S(g) + ____SO2(g)  _____S(s) + _____H2O(g)
3
Name:_______________________
8)12pts. Iron is important in the body primarily because it is present in red blood cells and acts to
carry oxygen to the various organs. There are about 2.6x1013 red blood cells in the blood of an
adult human, and the blood contains a total of 2.9 g of iron. How many iron atoms are there in
each red blood cell?
9)20pts. A sweetener has a molecular mass of 260 amu. Complete combustion of 2.540g a
sample of this sweetener yields 5.150g of CO2 and 1.760g of H2O. What are the empirical and
molecular formulas of the sweetener?
4
10) 20 pts 1.0 g of carbon dioxide was released from the reaction of a 4.00g piece of calcium
carbonate and 200.0 mL of 0.30 M of HCl(aq). (a) Which of the reactant is the limiting reactant?
(b) what is the percent yield? Note: the other two products of this reaction are water and calcium
chloride.
CaCO3(s) + 2HCl(aq)  CaCl2(aq) + H2O(l) + CO2(g)
5