"5 g" of copper was heated from 20^@"C" to 80^@"C". How much energy was used to heat the Cu? (specific heat for copper = ("0.38 J")/("g"*""^@"C").

1 Answer
Dec 19, 2017

~~"100 J" of energy are needed to heat the copper from 20^@"C" to 80^@"C".

Explanation:

The equation to use is:

Q=mcDeltat,

where:

Q is energy, m is mass, c is specific heat, and Deltat is change in temperature. Delta=(T_"final"-T_"initial")

Known

m="5 g"

c=("0.38 J")/("g"*""^@"C")

Deltat="80"^@"C"-"20"^@"C"="60"^@"C"

Unknown

Q

Solution

Plug the known values into the equation and solve for Q.

Q=(5color(red)cancel(color(black)("g")))xx((0.38" J")/("g"*""^@color(red)cancel(color(black)("C"))))xx(60^@color(red)cancel(color(black)("C")))="100 J" rounded to one significant figure