Unit 1 Section B - Looking at Water and Its Contaminants
Review
Name_________________
Physical Properties
1.
Name two physical properties would allow you to distinguish between liquid
water and rubbing alcohol.
Density
2.
A graduated cylinder has a mass of 125 g. When a sample of an unknown liquid
is placed in the cylinder, its new mass is 155 g. The volume of the liquid is
25 mL. What is the density of the liquid?
3.
If the liquid in question 2 is insoluble in water, will it sink or float in the water?
How do you know?
4.
A block has measurements of 6 cm, 17 cm, and 5.2 cm. The density of the block
is 1.85 g/cm3. What is the mass of the block?
Classification of Matter
5.
What does the symbol (aq) following the formula for a compound mean? Would
this substance be an element, a compound, a homogeneous mixture or a
heterogeneous mixture?
6.
7.
8.
Classify the following substances as pure substances or mixtures.
_____ a.
Cl2
_____ e.
oil and water
_____ b.
potassium
_____ f.
air
_____ c.
KCl(aq)
_____ g.
sedimentary rock
_____ d.
KNO3
_____ h.
a solution
Classify the following substances as an element, compound, homogeneous
mixture or heterogeneous mixture.
_____ a.
Cl2
_____ e.
oil and water
_____ b.
potassium
_____ f.
air
_____ c.
KCl(aq)
_____ g.
sedimentary rock
_____ d.
KNO3
_____ h.
a solution
Fill in the following data chart.
Substance
No
Did it show Tyndall
effect?
Yes
Gold in water from
stream
Amoxicillan
Yes
No
Yes
Yes
Polluted air
Yes
Yes
Jello
No
Yes
Milk
Did it settle out?
Is it a solution,
colloid or
suspension?
CuSO4(aq)
9.
Carbon tetrachloride, CCl4 is a liquid that can be used in dry cleaning. When
5.0 g of bromine is added to 75 g of clear colorless CCl4, the mixture has a
reddish brown color. Over time, no settling out is observed. When the mixture is
filtered, no residue is observed on the filter paper. When a light beam is directed
at the mixture, its path through the mixture is not visible. Is the mixture a
solution, colloid or suspension? Explain your answer.
10.
Show the formula for seven elements that exist in nature as diatomic molecules.
Symbols, Formulas and Equations
11.
Write a chemical equation that represents the following word equation:
Two atoms of potassium and one molecule of copper(II) chloride form two
molecules of potassium chloride and one atom of copper.
14.
Use the following reaction to answer the questions below
2 NaI
+
Cl2
→
2 NaCl
+
I2
a.
Write a sentence describing this reaction in terms of molecules.
(hint: use your common ions sheet to help name molecules)
b.
Did any elements react, or were they all compounds? Explain your
answer.
c.
Were any elements produced, or were they all products? How do you
know?
d.
Complete an atom inventory for the equation.
Reactants
Products
|
|
|
|
|
|
|
13.
Give the symbol for each element present in each molecule of Al2(SO4)3 and tell
how many of atoms of each element are present.
Electrical Charges, Protons, Electrons, Atoms and Ions
14.
15.
16.
17.
18.
Classify the following as anions, cations, or electrically neutral atoms.
_____ a.
Rb+1
_____ c.
Se–2
_____ b.
CrO4–2
_____ d.
Sn
Give the symbol and electrical charge for each of the following ions or atoms.
_____ a.
gold
____ protons
76 electrons
_____ b.
_________
2
protons
2 electrons
_____ c.
fluorine
9
protons
10 electrons
For each of the atoms or ions, identify the number of protons and electrons.
a.
P–3
_____ protons
_____ electrons
b.
Zn
_____ protons
_____ electrons
c.
Ba+2
_____ protons
_____ electrons
Give the symbol and charge for each of the following ions:
_____ a.
calcium atom that lost 2 electrons
_____ b.
nitrogen atom that gained 3 electrons
Were electrons gained or lost in order to form Be+2?
19.
Complete the following table.
Cation Anion Formula
Mg 2+
O2–
Al3+
Cl–
Mg2+
PO4–3
NH4+
CO32–
Name
Iron(III) sulfite
CdCl2
Cu(NO3)2
Aluminum hydroxide
20.
As an environmental chemist, you are testing for the presence of chloride ion in
samples of stream water. You perform the appropriate test on a sample for
Stream A and observe a white precipitate. The same test performed on a sample
from Stream B yields no change.
a. What can you conclude about the presence of chloride ion in Stream A?
b. Can you make a definite conclusion about the presence of the chloride ion in
Stream B? Why or why not?