Solid magnesium has a specific heat of 1.01 j/gâ°c. how much heat is given off by a 20.0 gram sample of magnesium when it cools from 70.0â°c to 50.0â°c?

404 J

Explanation:

The amount of heat given off by the magnesium sample is given by:

where

m = 20.0 g is the mass of the sample

is the specific heat capacity of the magnesium

is the change in temperature

Substituting into the equation, we find

and the negative sign means the heat is given off by the sample.

that's what i got you can count the number of atoms