If a catalyst changes the activation energy of a forward reaction from 28.0 kcal/mol to 23.0 kcal/mol, what effect does it have on the reverse reaction?

Explanation:

For an equilibrium reaction, the rate of forward reaction is equal to the rate of backward reaction.

As in the given reaction, change in activation energy is as follows.

                 (28.0 - 23.0) kcal/mol

                 = 5 kcal/mol

Therefore, when activation energy is increasing 5 kcal/mol for the given reaction in the forward direction then for the backward reaction there will be be a decrease of 5 kcal/mol.

Thus, we can conclude that if a catalyst changes the activation energy of a forward reaction from 28.0 kcal/mol to 23.0 kcal/mol, then it reduces the energy of activation of the reverse reaction by 5.0 kcal/mol.

1.solid

2.carbon dioxide

3.helium

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.