Last modified: Thu 07/28/2016 11:49:00 am CHEMACA

Oklahoma State University

It is OK to use your textbook or lecture notes from class, but if you can answers the questions without it that is OK too.

Do not press the RETURN or ENTER key while you are answering these questions. Your browser will interpret either the same as clicking on the Submit key.

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.

First Name:

Last Name:


1. When hexane, C6H14, is combusted in air, the products are carbon dioxide and water. When an amount of hexane 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 hexane.

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


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


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


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

2Ga(s)    +    3O2(g) -->  Ga2O3(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 .

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?