If irons temp goes from 50c to 75c in a 20g sample how many joules of heat were used

224.5J

Explanation:

Using the formula as follows:

Q = m × c × ∆T

Where;

Q = amount of heat (J)

m = mass of substance (g)

c = specific heat capacity.

∆T = change in temperature (°C)

According to this question;

m = 20g

∆T = 75°C - 50°C = 25°C

Q = ?

c of iron = 0.449 J/g°C

Using Q = m × c × ∆T

Q = 20 × 0.449 × 25

Q = 224.5J