6.0 g of copper was heated from 20 degree c to 90 degree c. How much energy was used to heat cu?

Copper heat capacity would be 0.385J/C*gram which means it needs 0.385 Joule of energy to increase 1 gram of copper temperature by 1 Celcius. The calculation would be:

energy = heat capacity * mass * temperature difference

energy = 0.385J/C*gram * 6g * (90-20)

energy = 161.7J