The formula for heat transfer is Q = mcΔT, where Q is heat, m is mass, c is specific heat capacity, and ΔT is the change in temperature. We are given Q = 300 J, m = 0.025 kg, and ΔT = 30 °C. We need to find c. Rearranging the formula, we get c = Q / (mΔT). Plugging in the values, c = 300 J / (0.025 kg * 30 °C) = 300 J / 0.75 kg·°C = 400 J/(kg·°C).