#"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
Meave60
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

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