How many joules of heat are needed to raise the temperature of 1.0-kg of aluminum from 22℃ to 55℃, if the specific heat of aluminum is 900 J/kg℃?

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

How is the atomic number of a nucleus changed by alpha decay

Imagine that a new planet is discovered with two moons of equal mass: moon a and moon b. the mass of the new planet is greater than the combined mass of its moons. moon a is farther away from the new planet than moon b. what is the planet's gravitational pull on moon a compared to the planet's gravitational pull on moon b? the planet's gravity repels moon a with a greater force than it repels moon b, which is why moon a is farther away. the gravitational pull on moon b is greater than on moon a because moon b is closer to the new planet than moon a. the gravitational pull on moon b is greater than on moon a because moon b is farther away from the new planet than moon a. the gravitational pull on moon a is the same as the gravitational pull on moon b because distance does not affect the planet's gravity.