What mass of a hot (85.0°C) aluminum rod (s = 0.900 J/°C•g) would need to be placed in 200. mL of water

Question

What mass of a hot (85.0°C) aluminum rod (s = 0.900 J/°C•g) would need to be placed in 200. mL of water (density = 1.00 g/mL, s = 4.184 J/°C•g) in order to increase the temperature of the water from 25.0°C to 30.0°C?

(Please show steps)

is it just (m * s * delta T) = - (m * s * delta T)?

Would the delta T for aluminum be 55 because it goes from 85 to 30 degrees celsius? And would the delta T for water be 5 degrees?

Answer 1

Yes to all your questions. q = heat = m*s*∆T and the heat gained by water must equal heat lost by Aluminum. So, you have it set up correctly, and need only solve for s of aluminum.