What is the Atomic mass and the mass number of Carbon?

Fill in the coefficients that will balance the following reaction: a0cr2(so4)3 + a1agno3

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.