A graduate-level laboratory investigation measures the average translational kinetic…
PHYSICS · Multi-part · CBSE · Physics · Kinetic Theory · Kinetic Theory
Problem
A graduate-level laboratory investigation measures the average translational kinetic energy per molecule, K_avg, of an ideal monatomic gas at several controlled temperatures.
The data collected are shown in the table below.
Temperature T (K)
K_avg (10⁻²¹ J)
150
3.1
250
5.2
350
7.3
450
9.4
550
11.4
(a) Sketch a graph of K_avg versus T using the data provided. Label both axes with appropriate scales and units.
(b) Using the graph or an appropriate calculation, determine an experimental value for the Boltzmann constant k_B from the slope of the best-fit line through the data.
(c) The universal gas constant R is 8.31 J mol⁻¹ K⁻¹. Using your experimentally determined k_B, calculate an experimental value for Avogadro’s number.
(d) Identify two plausible sources of systematic error in this experiment that could cause the experimentally obtained value of k_B to differ from the accepted value, and explain the effect each would have on the slope of the graph.