Unit 1 Gases
1.3 Exercises
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Section 1.3 Exercises
- Can the speed of a given molecule in a gas double at constant temperature? Explain your answer.
- A 1-L sample of CO initially at STP is heated to 546 °C, and its volume is increased to 2 L.
(a) What effect do these changes have on the number of collisions of the molecules of the gas per unit area of the container wall?
(b) What is the effect on the average kinetic energy of the molecules?
(c) What is the effect on the root mean square speed of the molecules?
Solutions
- Yes. At any given instant, there are a range of values of molecular speeds in a sample of gas. Any single molecule can speed up or slow down as it collides with other molecules. The average velocity of all the molecules is constant at constant temperature.
- (a) The number of collisions per unit area of the container wall is constant. (b) The average kinetic energy doubles. (c) The root mean square speed increases to [latex]\sqrt{2}[/latex] times its initial value; urms is proportional to [latex]\sqrt{E_{\text{K, ave}}}[/latex].
