Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chemistry 107

Chem 107

Hour Exam I
   Name
Fall 1996

(100 pts)
   Lab Section (circle): Tu Th

 

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(10) 1. Complete the following table:

Isotope A Z p n e
205Pb4+  
  143 96
Te2- 132  

 

 

(10) 2. Answer the following questions regarding the periodic table and the elements:

a. What is the charge on Group II-A ions?

b. What is the formula for elemental iodine?

c. Name an element occurring as a liquid at room temperature.

d. What charge would you expect for an Se ion?

e. What is the formula for elemental iron?

f. What is the general name for the Group I-A elements?

g. The elements with the lowest average ratios of neutrons to protons are located where on the Periodic Table?

h. Which element has the greatest attraction for electrons?

i. Which elements are called the halogens?

j. Which element would you expect to give up electrons most readily?

 

(8) 3. For each of the following compounds determine whether it is ionic or covalent.

 a. TiCl4   b. SiO2
 c. NH3  d. ZnS

 

(8) 4a. Imagine that you are given a sapphire (Al2O3) ring with a 1.50 carat stone in it. Having just finished chemistry, your immediate reaction of course is to figure out how many atoms of oxygen are in your new possession! 1.000 carat = 200.0 mg. Show your work in discovering this answer.

 

 

 

 

 

 

 

 

 

 

(2) 4b. How many formula units of aluminum oxide are there in this stone? Show work for credit

 

 

 

(12) 5. Name the compounds below.
a. KOH
b. Fe2(SO4)3
c. Na2O
d. Hg(C2H3O2)2
e. NH3
f. H3PO4

 

(12) 6. Write formulae for each of the following compounds.

a. Hydrogen cyanide

b. Ammonium hydroxide

c. Iron(III) chromate

d. Silicon tetrachloride

e. Plumbic oxide

f. Hydrochloric acid

(12) 7. Consider the reaction below:

  C4H10(g) + 02(g) Æ
   

 +
   

 

 

a. Balance the equation by placing the proper coefficients and compounds in the spaces provided.

b. How many moles of carbon dioxide may be produced by burning 8.50 grams of butane (C4H10) in air? Show work for credit

 

 

 

 

 

 

 

 

(6) 8. Define each of the following terms:

a. Orbital:

 

b. Actinide:

 

c. Mass number

(8) 9. Make each of the conversions below to the proper number of significant figures. Use exponential notation where appropriate!

a. 225.86 nm = m

b. 1.078 x 103 ° C = K

c. 54678.9 micrograms + 2.3 milligrams = kilograms

d. 345.0 cm x 3400 cm x 54.3786 cm = liters

 

(6) 10. a. Write a spectroscopic convention electronic configuration for:

Al

 

b. Write a Noble gas core convention electronic configuration for:

Pt

 

c. Write an orbital diagram convention electronic configuration for:

P

 

(6) 11. A student attempting to determine the density of ring to see if it was gold first weighed it in air on a triple beam balance, determining its weight to be 12.42 g. She then placed it in a cylinder filled to the 15.00 ml mark and then read a new volume of 16.2 ml. What is the density of this piece of jewelry? Is it gold? (The density of gold is 19.3 g/cm3. Show work!

 

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© R Paselk

Last modified 15 August 2005