Humboldt State University ® Department of Chemistry

Richard A. Paselk

 

General Chemistry

Spring 2011

 

© R. Paselk 2008
 
 

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Stoichiometry

Moles

1. How many moles of chlorine are there in 1.5 moles of iron(III) chloride?

2. How many moles of hydrogen are there in 0.763 moles of ammonium sulfide?

3. How many moles of aluminum are there in 2.34 g of aluminum foil?

4. How many moles of oxygen are there in a 76.94 g sample of air containing 19% oxygen?

5. How many grams of silver are there in 10.265 mol of silver phosphide?

6. How many grams of hydrogen would be needed to make 1.023 mol of ethanol (CH3CH2OH)?

Answers


In addition to these exercises you should familiarize yourself with the text materials.


Balancing Chemical Equations by Inspection

Balance the equations below by providing the proper coefficients:

(Examples 1-5 are answered with explanations, a-e are provided for extra practice - answers only are given.)

1. Al(s) + Fe2O3 (s) Fe(s) + Al 2O3 (s)

2. KClO3 (s) + heat KCl(s) + O2 (g)

3. C4H10 (g) + O2 (g) CO2 (g) + H2O(g)

4. N2 (g) + H2 (g) NH3 (g)

5. P4 (s)+ F 2 (g) PF5 (g)

Answers 1-5

a. Cu(s) + AgNO3 (aq) Cu(NO3)2 (aq) + Ag(s)

b. Fe(s) + O2 (g) Fe2O3 (s)

c. FeCl3 (s) + H2O(l) HCl(aq)+ Fe(OH)3 (s)

d. Zn(NO3)2 (s) + heat ZnO(s) + NO2 (g) + O2 (g)

e. H3PO4 (l) + heat H2O(l) + P4O10 (s)

Answers a-e


In addition to these exercises you should familiarize yourself with the text materials.


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© R A Paselk

Last modified 4 February 2009