The table shows the conditions during two trials of a reaction. Reaction Conditions Trial Temperature Catalyst 1 60 °C used 2 45 °C not used Assuming that other conditions remain the same during the two trials, which of the following is true for the reaction? The reaction pathway for the two trials is different. The activation energy barrier is lower during Trial 2 than Trial 1. The same number of reactant particles reached the transition state in Trial 2 as in Trial 1. The number of particles having the required activation energy is higher for Trial 2 than Trial 1.

Calculate the frequency of a wave in a spring toy. the wave has a speed of 1.1 meters per second and a wavelength of 0.1 meters. *

Suppose a pair of chemical compounds a and b can react in two different ways: a + b -> c reaction 1 gives product c. a + b -> d reaction 2 gives product d. the following facts are known about the two reactions: . reaction 1 is endothermic and reaction 2 is exothermic. if a reaction vessel is charged (filled) with a and b , then at first d is produced faster than c. use these facts to sketch a qualitative reaction energy diagram for both reactions. note: because these sketches are only qualitative, the energies don? t have to be exact. they only have to have the right relationship to each other. for example, if one energy is less than another, that fact should be clear in your sketch.

Which of the following reactions is endothermic? h2(g) + ½ o2(g) h2o(g), h = -57.82 kcal ½n2(g) + o2(g) + 8.1 kcal no2(g) ½ n2(g) + 3/2 h2(g) nh3(g) + 11.0 kcal c(diamond) + o2(g) co2, h = -94.50 kcal