Chemistry January Exam Review#1

 

1. The explosion of Chinese gunpowder can be represented by the following equation:

4 KNO3(s) + 7 C(s) + S(s) ----> K2CO3(s) + K2S(s) + 3 CO(g) +3 CO2(g) + 2 N2(g)

 

a. At STP, how many litres of N2 will be produced along with every 2.0 moles of CO2 ?

b. Find the volume of CO formed at 50 C and 101.3 kPa when 3.5 moles of carbon react.

R = 8.31 L kPa/(mole K)

 

2. Given:

3 C2H6O(g) + 4 H2CrO4 + 12 HCl ---> 3 C2H4O2 + 4 CrCl3 + 13 H2O(l)

 

At STP, 4 ml of C2H6O vapour are bubbled into a solution of chromic and hydrochloric acids. How many grams of water will be formed if all the C2H6O reacts?

 

3. Give a detailed account of what occurs at the molecular level when a solid sublimates.

4. Do all molecules at the same temperature have the same speed? Explain.

5. A student would like to heat a sample of hydrogen gas from 300K to 350K. By what factor will he increase the pressure of the gas if he makes sure that the volume remains constant ?

6. 0.8016 g of an element are vapourized(turns into a gas) in a 300 mL flask. The pressure gauge reads 101.3 kPa when the gas' temperature is the same as that of the 45.0 C water bath.

Identify the element famous for melting in your hand.

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Created:April/6/1996; Updated:Dec/3/2009