Chemistry Exam 1
Please complete the following, be sure to show all relevant work. (151 pts)
Good Luck!
1. Define the following: (5 each)
a. Atom
b. Element
c. Extensive property (define and give an example)
b. Compound
2. Are the following chemical or physical changes? (2 each)
a. cooking an egg
b. cutting stone
3. Express the following amount using a more appropriate SI prefix
(For example, change 2700mL to 2.7L) (5 each)
a. 0.000006 meters
b. 120,000 joules
4. If a sample of an unknown substance has a mass of 47 grams and a volume of 21 cm3,
what is the sample’s density? (5)
5. Convert 23 cm into meters. (5)
6. If the theoretical yield of reaction is 23 grams, and the actual yield is 14.5 grams, what is
the percent error? (5)
7. How many significant figures are there in the following measurements: (3 each)
a) 28.6 g
b) 3440. cm
c) 91000 m
d) 0.04604 L
e) 0.00067000 kg
8. Perform these calculations on your calculator. Give answers to the correct number of
significant figures and units. (4 each)
a) 5.44 m – 2.6103 m
b) 2.4 g/mL x 15.82 mL
c) Polycarbonate plastic has a density of 1.2 g/cm3. A photo frame is constructed of 2
sheets of polycarbonate that are each 3mm thick. If the frame measures 28 cm by 22
cm, what is the total mass of the frame?
9. What does the atomic number tell you about an element? (5)
10. What is an isotope? (5)
11. What is the mass in grams of 0.733 mol of the element Chlorine, Cl? (5)
12. How many moles of gold, Au, are there in 3.60x10-10 g of gold? (5)
13. What is the mass in grams of 5.0x109 atoms of Neon, Ne? (5)
14. What mass of silver, Ag, contains the same number of atoms as 10.0 g of boron, B? (5)
15. Given the following expression, 1s2 2s2 2p1:
a) Describe what the first numbers, letters, and the superscript numbers represent. (5)
b) Which element does this represent, and why? (5)
16. Write the complete electron configuration for the element cobalt, Co. (5)
17. Use Noble Gas configuration to write the electron configuration for the element
yttrium, Y. (5)
18. Show the complete orbital notation for the element sulfur, S. (5)
19. Using just a periodic table and your knowledge of trends: (5 each)
a) Put the elements zinc, flourine, and strontium in order of smallest to largest atomic
radii.
b) Put the elements Hf, Ga, and Ti in order of smallest to largest ionization energy.
c) How is the radius of the oxygen ion, O2-, compare to the radius of a neutral O atom?
d) Which element is more electronegative, Calcium or Bromine? Explain why.