Iam horrible at chemistry, can somebody me out with this question .
carbonic acid (h2co3) forms when carbon dioxide (co2) dissolves in water according to this equation:

co2 + h2o→h2co3

how many moles of co2 must dissolve in an excess of water to produce 4 moles of h2co3 ?
a. 1 mol
b. 2 mol
c. 3 mol
d. 4 mol

Match the following vocabulary terms to their definitions. 1. amount of energy required to change 1 gram of material from the solid to the liquid state at its melting point 2. a measure of the kinetic energy of the particles of a substance 3. the amount of heat energy required to raise the temperature of 1 gram of liquid water from 14.5°c to 15.5°c 4. amount of energy required to change 1 gram of material from the liquid to the gaseous state at its boiling point 5. the amount of energy required to change 1 gram of a substance 1°c a. temperature b. latent heat of vaporization c. latent heat of fusion d. calorie e. specific heat

Can someone me with 3 and 4 plz. this is for masteries test.

The identities of substances are the same before and after which type of change