Calculate the amount of heat transferred in each of the following cases:
(Be sure to include all calculations (Use GRASP )
a) 500 grams of frozen water (ice) melts.
b)120 g of water warms from 10°C to 120°C.
c)95 g of water cools from 70°C to 32°C.
d) 3.3 kg of aluminium cools from 45°C to 25°C.
Please tell me what GRASP stands for? Probably a mnemonic to help memorize the formula.
a. q = mass H2O x delta Hfusion H2O = ?
q = 500 g x (look up heat fusion of ice in J/g) and solve.
b. three stages as follows:
q1 = change in heat going from 10 C to 100 C.
q1 = mass H2O x specific heat H2O x (Tfinal - Tinitial)
q1 = 120 g x (look up specific heat H2O x (100 - 10) = ?
q2 = change in heat to convert liquid water @ 100 C to steam @ 100 C.
q2 = mass H2O x delta Hvaporization of H2O
q2 = 120 g x (look up delta H vap of water @ 100 C) = ?
q3 = change in heat from heating steam from 100 C to 120 C
q3 = mass steam x specific heat steam x (Tfinal-Tinitial).
q3 = 120 g x (look up specific heat steam) x (120-100) = ?
Total change in heat Q = q1 + q2 + q3. What the individual values of q1 and q2 and q3 to make sure the units are the same before they are added.
c. q = mass H2O x specific heat liquid water x (Tfinal-Tinitial)
q = 95 x look up specific heat liquid water x (32 - 70) = ?
d. q = mass Al x specific heat Al x (Tfinal - Tinitial)
q = 3300 g x look up specific heat Al in J/g x (25-45) = ?
Note that some of the calculations give a positive sign and some give a negative sign. From the way the problem is stated asking for the AMOUNT of change and not sign I think that means to ignore the sign and assume all of the final answers are positive. Post your work if you get stuck.