Last modified: Wed 12/31/1969 06:00:00 pm CHEMACA

Oklahoma State University

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Answer all of the questions below. If you do not know an answer enter CNA. However, it will help me the most if you answer each question with your best intuition/idea about what would be a reasonable answer.


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1. When pentane, C5H12, is combusted in air, the products are carbon dioxide and water. When an amount of pentane and an amount of oxygen are mixed in a particular experiment 100. grams of carbon dioxide are produced.

a) Write a balanced chemical equation for the combustion of pentane.

b) How many moles of CO2 are produced in the reaction?

mol

c) How many moles of H2O are produced in the reaction?

mol

d) Calculate the mass of pentane required to produce 100. grams of carbon dioxide.

grams

2. Gallium (III) oxide is used in semiconductors, and is formed when elemental gallium reacts with oxygen according to the reaction;

4Ga(s)    +    3O2(g) -->  2Ga2O3(s)

In a particular experiment 20.0 g gallium are mixed with 15.0 g of oxygen and allowed to form the product. Complete the ICE Table below .

 
REACTANTS
REACTANTS
PRODUCTS
Exp.
4Ga(s)
3O2(g)
--->
2Ga2O3
Initial Amount
Change Amount
Final Amount
 

a) Which substance is the limiting reagent?

b) Calculate the mass Ga remaining after the reaction is over.

grams Ga

c) Calculate the mass O2 remaining after the reaction is over.

grams O2

3. Is there anything about the questions that you feel you do not understand? List your concerns/questions.

4. If there is one question you would like to have answered in lecture, what would that question be?