Answer:A. An increase in temperature increases the reaction rate.
Explanation:because of the disproportionately large increase in the number of high energy collisions. It is only these collisions (possessing at least the activation energy for the reaction) which result in a reaction.
Very simply, you get twice as much Hydrogen as Oxygen, because the chemical formula is H2O, meaning two hydrogen atoms bonded to one oxygen atom.
Answer: The new volume of cake is 1.31 mL.
Explanation:
Given:
= 0.20 mL, 
= ?, 
Formula used to calculate new volume is as follows.

Substitute the values into above formula as follows.

Thus, we can conclude that the new volume of cake is 1.31 mL.