Chemistry – Midterm Part 1 Water Unit
Review packet 2013-2014
Lab Equipment, Reports and Safety:
Big Ideas:
1. Laboratory equipment has specific uses, and also limitations on their uses.
2. Each piece of equipment provides data with specific units.
3. Safety rules and procedures are designed to protect you from contact with chemicals and
broken glass. Cuts from broken glass is one of the most common injuries in the chemistry lab.
4. Your eyes must always be protected with safety goggles.
1. What equipment is used to measure each quantity below? What is the unit of the measurement?
a. mass
b. volume
c. temperature
d. length or any other linear dimension
2. Explain what it means to “tare” a balance.
3. Before you heat up a beaker, you should inspect the beaker for the presence of
________________________.
Water Unit:
Big Ideas:
1. Chemists use the metric system when recording their measurements.
2. Dimensional analysis must be used to convert between measurement units.
3. Chemicals have both physical and chemical properties that can be used to tell them apart, and also
to separate components of a mixture.
4. Water’s polarity makes it an excellent solvent.
5. When it comes to evaluating a solute/solvent relationship, remember the phrase
“like dissolves like.”
6. Solubility can be quantified with a solubility curve, and by calculating the % concentration of a
solution.
7. An imbalance of H3O+ and OH- ions causes solutions to be either acidic or basic.
1. Classify each as a solution, colloid, suspension or pure substance.
a. foul water
b. Kool aid
c. tap water
d. distilled water
e. clean air
f. dusty air
2. What is the Tyndall test? When would you use it?
3. Fill in the blanks. Show the DA work in the space to the right.
a. 500 m = ________ km
b. 0.25 cm = ________ mm
c. 1 m = ________ km
d. 5 x 102 mm = _________ m
4. Write the formula for density. What units are densities reported in?
5. What is the mass of a 15.2 cm3 block of steel? The density of steel is 8.0 g/cm3. Show the math
work.
6. Identify the following as physical or chemical property.
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
density
surface tension
liquid at room temperature
boiling point
reacts with an acid to produce H2 gas
electrically conductive
dissolves ionic compounds
breaks down into H2 (g) and O2 (g)
red color
inert
7. Draw and label a picture of a water molecule. Explain it in terms of being polar. Show hydrogen
bonds between different water molecules.
8. Explain how you use the solubility phrase” like dissolves like.”
9. In a sample of salt water, state what the solute and solvent are.
10. Is salt water a homogeneous or heterogeneous sample? Explain.
11. Write the formula for calculating the pph of a solution.
12. Write the formula for calculating the ppt of a solution.
13. What is the pph concentration of a solution containing 15 g salt and 80 grams of water?
Use the following two graphs to answer questions 14 – 19.
14.
What mass of KNO3 will dissolve in 100 g of water at 30°C?
15.
What mass of KBr will dissolve in 75 g water at 30°C?
16.
25 g of NaNO3 is dissolved in 100 g of water at 30°C. Is this solution saturated, unsaturated
or supersaturated?
17.
In order to make this solution saturated, how much more NaNO3 must be added?
18.
What is the minimum mass of water needed to dissolve 10 g KBr at 60°C?
19.
What mass of nitrogen can be dissolved in 100 g of water at 40°C? At 10°C?
20. Acids have pH values between _____ and _____.
21. A neutral solution has a pH of _____.
22. Which are the heavy metal ions? Why is it a problem we should try to fix?
Electrons (part of Water unit):
Big Ideas:
1. The atomic number of an element indicates its number of protons, and also the number of
electrons in the neutral atom.
2. Electrons are located in energy levels, sublevels, and orbitals.
3. An electron configuration gives information about which levels and sublevels the electrons
are in.
4. An orbital box diagram uses “arrows” and “boxes” to show which orbitals the electrons are in.
5. The valence electrons are involved in bonding. Atoms gain or lose those electrons to
become ions.
6. Lewis dot (electron dot) diagrams are used to show the number of valence electrons in an atom.
1. Complete the table.
Element name &
symbol
Atomic
number
# of
electrons
in neutral
atom
Electron configuration
(may use noble gas
shortcut)
aluminum, Al
20
52
manganese, Mn
7
2. Label the blank PT with the s, p, and d “blocks”.
3. Complete orbital box diagrams for the elements below.
a. Carbon
b. Magnesium
Predicted
ion
charge
(sign and
number!!)
Electron configuration of
ion
4. Draw Lewis dot symbols for the following atoms:
a. boron
b. zinc
c. lithium
5. What are the rules for predicting charges of ions?
Remember – it has to do with the number of valence electrons.
Ionic Compounds (part of Water unit):
1. Positive ions are called ___________________ and negative ions are called ___________________.
2. Metals form (positive / negative) ions.
3. Give 3 examples of common polyatomic ions. State their name, formula and charge.
4. Why do some metals like iron and copper require a Roman numeral in their name?
5. The “Tooth and Notch” technique was helpful in determining ionic formulas. Create a tooth and
notch for the compound calcium iodide.
6. Write the formulas for the compounds formed between the element or ion pairs listed below:
Remember…balance the charges!
calcium and oxide
sodium and fluoride
aluminum and sulfate ion
lead(II) and carbonate
lithium and hydroxide
gallium and hydroxide
beryllium and nitride
cobalt(IV) and phosphate