Why does a higher temperature have more of an effect on materials during chemical weathering

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Which statement is usually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.

How many moles of al3+ ions are in 1.25 moles of al2o3