1. First Term Review
Instructions: Answer the following questions. Type your answers except for the
mathematical problems (those should be done by hand).
Some of the questions will be counted toward extra points for other assignments
but you should answer all questions.
Review is due on Friday September 2nd, 2011.
1. Define the following words if pertainable give examples:
Chemistry
Matter
Substance
Sustainability
Mass
Weight
Model
Atomic level
Energy
Elements
Compounds
Homogenous mixtures
Heterogeneous mixture
Electron
Proton
Neutron
Subatomic particles
Nuclide symbol and its parts
2. What are CFC’s? How do they affect our environment?
3. Give three examples of SI units and what they measure.
4. What are prefixes used for?
5. Describe three phase changes and where they can occur.
2. 6. What’s the difference between intensive and extensive properties? Exemplify
your answer.
7. Do chemical reactions affect our environment? How? Give specific examples.
8. What law does the following scenario describe?
One gram of Sodium Chloride always contains 0.3934 grams of Sodium
and 0.6066 grams of Chlorine.
9. Describe the following as a cation, anion, or polyatomic ion.
Ni2+
Te2-
NH4+
N3-
Rb+
HPO42-
10. How are isotopes differentiated?
11. Make a time line of the evolution of the atomic theory (write scientist names
and their experiments).
12. What information about an element can you find in the periodic table?
13. Write the formula for the following ionic compounds:
Fe2+ PO43- Iron (II) Phosphate Fe3(PO4)2
Ti4+ O2- Titanium (IV) Oxide Ti2O4
2+ -
Mg Br Magnesium Bromide MgBr2
3. 14. Using the following data, calculate the average atomic mass of an unknown
element and determine what element it is:
Mass number Isotopic Mass (amu) Fractional Abundance
50 49.9461 0.0435
52 51.9405 0.8379
53 52.9407 0.0950
54 53.9389 0.0236
Average Atomic Mass = (49.9461)(0.0435) + (51.9405)(0.8379) +
(52.9407)(0.0950) + (53.9389)(0.0236)
Average Atomic Mass = 51.9956 amu
Chromium
15. Two samples of different compounds of nitrogen and oxygen have the
following composition. What are the two compounds? What law can you use to
solve this problem?
Amount N Amount O Mass ratio (O g/N g)
Comp A 1.206 g 2.755 g 2.755/1.206 = 2.2844
Comp B 1.651 g 4.714 g 4.714/1.651 = 2.8551
Whole Small Number Ratio = 2.2844/2.8551 = 1.2499 = 1.25 = 5/4
Compound A – NO4
Compound B – NO5
16. What is the mass percent of carbon in CH2O?
Mass percent = mass of element / total mass * 100
Mass percent = 12.011g/mol / (12.011 + 2*1.01 + 15.999) g/mol * 100
Mass percent = 39.997 %
17. The world’s oceans contain approximately 1.35 x 109 km3. What is the
volume in liters?
1.35 x 109 km3 (1000 m)3 (10 dm)3 1L = 1.35 x1021 L
(1 km)3 (1 m)3 1 dm3
18. A sample of nitrogen gas in a glass bulb weighs 243 mg. What is this mass in
SI base units of mass?
243 mg 1g 1 kg = 2.43 x10-4 kg
1000 mg 1000 g
4. 19. Identify a substance that when poured into a graduated cylinder the volume is
35.1 mL and has a mass of 30.5 g.
Substance Density (g/mL)
n- butyl alcohol 0.810
ethylene glycol 1.114
isopropyl alcohol 0.785
toluene 0.866
1. Find the density of the substance you have: D = 30.5 g / 35.1 mL =
0.869g/mL
2. Compare it to the given chart: Toluene
20. Write the following in terms of the SI base unit (write them in scientific
notation)
a. 1.07 ps b. 5.8 micrometer
c. 19.6 ms d. 15.3 ms
a) Base unit for time: seconds
1.07 ps 1s = 1.07x10-12 s
1x1012 ps
b) Base unit for length: meter
5.8 micrometers 1 meter = 5.8x10-6 meters
1x106 micrometers
c) Base unit for time: seconds
19.6 ms 1s = 1.96x10-2 s
1000 ms
d) Base unit for time: seconds
15.3 ms 1s = 1.53x10-2 s
1000 ms
21. Tungsten metal, which is used in light bulb filaments, has the highest melting
point of any metal (3410oC). What is the melting point in degrees Fahrenheit?
F = 1.8C + 32 à F = 1.8(3410) + 32 = 6170 F
22. How many atoms of Pd are in 3 grams of Palladium? (Hint: use average
atomic mass in amu or g/mol and Avogadro’s number).
1. Find the average atomic mass of Palladium: 106.42 g/mol
3g mol 6.023x1023atoms= 1.698x1022 atoms
106.42 g mol
5. 23. What element do I have in a sample with a mass of 3 grams and about
2.287x1022 atoms.
1. In order to identify the element you need to find its average atomic mass.
3g 6.023x1023 atoms = 79.007 g/mol
2.287x1022 atoms mol
24. What do Pauli’s exclusion principle and Hund’s rule state?
25. Give the electric configuration of the following elements.
Ca
I
Mg
N
Al
