Question

SAT M 10 26. 750K 500K Relative number of molecules 250K Calculators are permitted A chemistry teacher is giving a les- son on the kinetic molecular the- ory of gases. She explains to her students that they will be making graphs of the distribution of differ- ent speeds of molecules of an un- known gas at varying temperatures. At a given temperature, the graph peaks at the speed at which most molecules are moving. As the tem- perature is increased, the most prob- able speed increases, but the curve becomes broader because the spread of speeds increases. Given this in- formation, which of the following graphs could represent the distribu- tion of the molecular speeds of the unknown gas at various tempera- tures? Velocity (m/s) 250K Relative number 9 of molecules 500K 750K Velocity (m/s) 250K 500K 750K Relative number of molecules Velocity (m/s) 750K 500K 250K Relative number of molecules Velocity (m/s)

Answer 1

Given that 1) The graph shows peak molecules are moving, at which most As Temperature increases, speed cvelocity) also increases low temperature - high temp. velocity increase

9) If speed increases, curve become broaden It means this curve has lower peak Becase highly spread curve has less peak see following curve ne less spread Chigh peak) Nk more spread (low peak) Au these conditions are satisfied by curves in Ophion 050k I 5ook 750K Relative no 0 molecules velocity - See as temperature increases, speed also increase which impuse more broader curve with increasing temp.