NAME: _______________________________
YOUR MAJOR: _______________________________
QUIZ 1 – Chapter 1 and 2
L-321 (Sept 19, 2005)
11:05 am to 12:15 pm class
1. a) Draw a picture showing a neutral sodium atom. Be sure to label how many
subatomic particles (neutrons, electrons, and protons) there are and where they are
located (in a general sense).
b) Indicate the number of protons, neutrons and electrons in a Ca2+ ion
c) What is a general term used for ions which are positively charged?
_________________________
2.
Write the formula for:
(a) sodium phosphite
(b) the compound that results when the elements hydrogen and selenium react
3.
Name the following and state whether it is IONIC or MOLECULAR:
(a) CuO
_____________________________________
(b) Cr2(SO4)3
_______________________________________________________
(c) S4N4
_______________________________________________________
(d) CO2
_______________________________________________________
4.
A student needs a sample of Fe(NO3)3 . 9H2O, but when she went to the latest
edition of the catalog of the major chemical supplier, she could not find it listed
alphabetically under “iron”. Knowing that suppliers of laboratory chemicals still often
list chemicals under their older names, what name should she look for in the catalog?
5.
There are three naturally occurring isotopes of magnesium. Their masses and
fractional abundances are:
23.985042 amu, 0.7899 %
24.985837 amu, 0.1000 % and
25.982593 amu, 0.1101 %
Calculate the weighted average atomic mass of magnesium.
6.
Write the formula for the following:
(a) Potassium carbonate
____________________
(b) Calcium chloride
____________________
(c) Iron (III) sulfide
____________________
(d) Manganese (II) sulfate
____________________
7.
Ammonia is composed of hydrogen and nitrogen in a ratio of 9.33 g of N and 2.00
g of H. If a sample of ammonia contains 6.28 g of H, how many grams of
nitrogen does it contain?
8.
A compound whose common name is green nitrol has the chemical formula
FeSO4 • 7H2O. What is the chemical name of this compound?
9.
Which one of the following is a physical change?
a. when ignited with a match in open air, paper burns
b. in cold weather, water condenses on the inside surface of single pane
windows
c. when treated with bleach, some dyed fabrics change color
d. when heated strongly, sugar turns dark brown
e. grape juice left in an open unrefrigerated container turns sour
10.
Uranium exists in nature in the form of several isotopes; the different isotopes
have different ______________________________.
BONUS QUESTION:
Naturally occurring silver consists of two isotopes
107
109
Ag, 106.905092 u
Ag, 108.904757 u
A meteorite (or more properly, an extra-terrestrial object) which was retrieved
from the ocean floor by one of the Explorer vessels contained a high percentage
of silver. Oddly however, even though the silver contained the same two isotopes
as our natural silver, the average atomic weight of the silver in this object, as
verified by several reputable scientific laboratories in the United States and
abroad, gave a value of 108.548 u! From this data, calculate the percent of the
107
Ag isotope in the object retrieved from the ocean floor.