7. What is the mass of a piece of copper (Cu) that undergoes a 25.0 °C temperature change with the loss of 428 J of energy?

0.0428 kg or 42.8 g

Explanation:

Applying,

Q = cmΔt Equation 1

Where Q = heat lost of heat gained, c = specific heat capacity of copper, m = mass of copper, Δt = temperature change.

make m the subject of the equation above

m = Q/cΔt Equation 2

From the question,

Given: Q = 428 J, Δt = 25 °C

Constant: c = 400 J/kg.°C

Substitute these values into equation 2

m = 428/(25×400)

m = 0.0428 kg

m = 42.8 g

i'm pretty sure its b i might be wrong though!

give me abc and i will get it for u.