Chemistry
Name: ___________________________________________
Water Section C Reading Guide
Date: ______________________________ Period: _____
Section C.1
1. Define solubility: ________________________________________________________________________________________________
________________________________________________________________________________________________
2. Only 2 factors will determine whether 25 grams of a solute like NaCl will dissolve in a sample of water.
What are those two factors?
____________________________________
____________________________________
3. A solution has undissolved solute settled at the bottom, even after it is stirred well. Is this solution
saturated, unsaturated, or supersaturated? Circle your choice.
4. Use the solubility curve provided to answer these questions.
a. Which solute has a solubility that is the least
temperature-dependent?
b. There is one gaseous substance shown on this
curve. Identify it.
c. How many grams of ammonium chloride will
dissolve in 100 g of water at 70°C?
d. If you have 75 grams of 30°C water, what is the
maximum amount of sodium nitrate you can dissolve?
e. If a saturated solution of NH4Cl (in 100 g of water)
at 90°C is cooled to 15°C and remains supersaturated,
how many grams of solute can be forced to
precipitate out of solution?
Section C.2
1. Define solution concentration: ________________________________________________________________________________
________________________________________________________________________________
2. 0.14 grams NaCl is dissolved in 4500 g water. Calculate the concentration in pph and ppm.
3. The concentration of lead(IV) ion in a water sample is found to be 5 ppm. How does this concentration
compare to 5 ppb – greater or smaller?
Section C.4
1. Explain, with words and a picture, how water is classified as a polar molecule.
(There is a nice picture on p.52)
2. Water is a ( linear / bent ) molecule.
3. When water molecules dissolve an ionic compound, “hydration spheres” of water molecules form
around the individual ions. Draw correctly-oriented water molecules around the individual ions
below, to illustrate these “hydration spheres.”
Na+1
Cl-1
3. In the chemical formula NH4Cl, there are ___ N atoms, ___ H atoms, and ___ Cl atoms.
4. What is the name of this compound? ___________________________________.
Section C.5
1. Why are Pb+2 and Hg+2 ions called “heavy-metal” ions? (no – they don’t like loud music)
2. List a few commonplace sources of lead ion.
3. List a few commonplace sources of mercury ion.
4. Describe the origin of the term “mad as a hatter.”
5. Which 1865 novel by Lewis Carroll includes a character named the “Mad Hatter”?
Section C.6
1. The pH scale ranges from ___ to ___ .
2. A pH value less than 7 indicates an (
acidic / basic ) solution.
Neutral pH is a value of _____.
3. Changes in pH do not directly relate to concentration changes. For example, lemon juice, with a pH of 2
is ____ times more acidic than soda with a pH of 3.
4. An acidic substance is one that releases (H+ / OH-) ion in solution.
5. A basic substance is one that releases (H+ / OH-) ion in solution.
6. OH- ion is named ______________________. (Look at your table of polyatomics)
7. The EPA requires drinking water to be within the pH range from ______ to ______.
Section C.7
1. Sugar and ethanol are classified as molecular, and not ionic, substances because they ____________________
_____________________________________________________________________________________________________________________.
2. Ionic substances are crystalline solids at room temperature. Molecular substances, on the other hand,
are found in which states of matter at room temperature? __________________________________________________.
3. Define electronegativity: ______________________________________________________________________________________.
4. A molecular substance will dissolve in water if ________________________________________________________________
_____________________________________________________________________________________________________________________.
5. Explain the solubility rule “like dissolves like.” _____________________________________________________________
_____________________________________________________________________________________________________________________.
Section C.9
1. Gas solubility is much (greater
/ less ) than solid solubility.
Section C.10
1. A long stretch of hot summer days can cause a devastating fish kill to occur. Explain this in terms of
oxygen gas solubility.
2. Describe “gas-bubble trauma,” and what events can cause it to occur in fish.
Ionic formula writing
1. Complete the chart for each compound below. The first compound is completed for you as an example.
compound name
cation symbol and
name
anion symbol and
name
ionic formula
sodium fluoride
sodium ion, Na 1+
fluoride, F 1-
NaF
magnesium hydroxide
Ba(NO3)2
lithium sulfate
mercury(II) phosphide
PbCl4
Cu3PO4
tin(IV) carbonate
copper(II) sulfide
AgBr
ammonium dichromate
K2C2O4
Fe(C2H3O2)3
2. Why do some metals like copper, lead and iron require a Roman numeral in their compound name?
3. Why is this ionic formula incorrect?
ZnI3
Explain the mistake, then write the correct formula.
4. Sulfate, sulfite, sulfide and sulfur are names of 3 different chemicals. Write their symbols and charges.
sulfate
sulfite
sulfide
sulfur
No textbook questions are assigned with this reading guide