- positive q = system has gained heat from the surroundings (endothermic)

- negative q = system has released heat to the surroundings (exothermic)

- specific heat = measure the change in temperature that a known mass undergoes as it loses or gains a specific quantity of heat

Formulas to know:

q = m^{.}C^{.}∆T and q_{lost}= q_{gained}which means, m_{lost}^{.}C_{lost}^{.}∆T_{lost}= m_{gained}^{.}C_{gained}^{.}∆T_{gained}

∆T means a change in temperature represented by taking the final temperature minus the initial temperature.

Mass = 95.4 grams

Heat = 849 J

Initial Temperature = 25.0ºC

Final Temperature = 48.0ºC

Specific Heat (C) = ?

849 J = (95.4 grams) (C) (48.0ºC - 25.0ºC)

849 J = (95.4 grams) (C) (23ºC)

849 J = 2194.2 C

849 J/2194.2 = 2194.2/2194.2 C

C = 0.387 J/gºC

m

(50 grams) (4.184 J/gºC) (89ºC - x) = (25 grams) (4.184 J/gºC) (x - 23ºC)

(209.2) (89ºC - x) = (104.6) (x - 23ºC)

18618.8 - 209.2x = 104.6x - 2405.8

18618.8 + 2405.8 = 104.6x + 209.2x

21024.6 = 313.8x

21024.6/313.8 = 313.8/313.8 x

x = 67ºC