Chemistry II Unit 1 Review Assignment
1. What is the purpose of significant figures?
To communicate the precision of the tools used to other scientists
2. What is the purpose of the silly 5 rule?
To avoid artificially inflating data by always rounding up on the half-way mark
3. Compare and contrast ionic, covalent, and metallic bonding
- Ionic: electrons are transferred from metal to nonmetal; atoms stick together because
they have opposite charges
- Covalent: Electrons are shared between two nonmetals; atoms stick together because
they are both holding on to the same electrons (technically, this one is the only actual
“bond”)
- Metallic: all the metal ions release electrons into a “sea” and the newly formed positive
ions are attracted to this negative “sea”, not each other
- Acids: Covalent bonds that are almost ionic. Hydrogen atoms pretty much release their
electrons to a nonmetal and act like H+ ions. We will treat them like this most of the time.
4. Compare and contrast beakers, flasks, and graduated cylinders.
- Beaker: wide bottom, straight sides, pouring spout; used for containing or transferring
liquids; NOT for measuring
- Flask: wide bottom, narrow mouth, sloped sides, no spout; used for reactions;
Erlenmeyer are NOT for measuring, but volumetric flasks will measure a single volume
- Graduated cylinder: Narrow bottom, straight sides, pouring spout; Used for measuring
liquids
5. Compare and contrast graduated cylinders, volumetric pipets, and burets.
- Graduated cylinder: Least precise but easiest to use; marked TC, but really not precise
enough to make that big of a difference, best for general use
- Volumetric pipets: Used for delivering a single, specific volume; marked TD; are very,
very precise (4 decimal places)
- Buret: can be used to deliver any number of volumes; marked TD; markings are “upside
down” (zero is at the top); medium precision (2 decimal places)
- Volumetric flasks (even though I didn’t ask): used to contain a single volume; marked
TC; medium-high precision (2-3 decimal places, depending on the size)
6. What first aid/emergency procedures would you perform if… you can figure this one out…
a. You were on fire
b. A beaker was on fire
c. You spilled an acid on the desk
d. You spilled a toxic chemical on your pants
e. You broke a beaker and cut yourself
7. How many significant figures are in the following?
a. 0.00250 g 3
b. 1.000 s 4
c. 6.5 m 2
d. 25 rubber duckies infinite
8. Round the following to 3 significant figures:
a. 1.253 g 1.25 g
b. 82.65 m 82.6 m
c. 19.75 kg 19.8 kg
d. 1879.2 N 1880 N
9. Calculate the following and round to the correct number of significant figures
a. 1.28g/1.9 mL 0.67 g/mL
b. (23.95 cm)(2.85 cm) 68.3 cm2
c. 102.6 g + 12.85 g 115.4 g
d. (6.5 g + 9.5 g + 3.8 g)/3 trials 6.60 g/trial
10. Name the following:
a. Mg(NO3)2 Magnesium nitrate
b. CCl4 Carbon tetrachloride
c. FeCrO4 Iron (II) Chromate
d. S2O5 Disulfur Pentoxide
e. H2CO3 Carbonic acid
f. HCl Hydrochloric acid
11. Give formulas for the following:
a. Sodium phosphate Na3PO4
b. Tin (II) permanganate Sn(MnO4)2
c. Diphosphorus hexachloride P2Cl6
d. Ammonia NH3
e. Barium dichromate BaCr2O7
f. Nitrous acid HNO2
g. Hydrocyanic acid HCN
12. Convert the following:
a. 1.85 x 1012 nm to m
1.85 x 1012 nm
10-9 m
☺
1 nm
= 1.85 x 103 m
b. 7.21 x 10-3 kg to Mg
7.21 x 10-3 kg
103 g
1 Mg
☺
1 kg
106 g
= 7.21 x 10-6 m
c. 15.1 m/s to km/hr
15.1 m
1 km
60 s
60 min
= 54.36 km
s
1000 m
1 min
1 hr
hr