Question

The specific heat capacity of silver is 0.24 J/g ·°C

a. What additional piece of information is needed to calculate the molar heat capacity of silver (6 points)?

b. Calculate the energy required to raise the temperature of 245.0 g Ag from 273 K to 373 K? (6 points)

c. It takes 65 kJ of energy to raise a sample of silver from 298 K to 363 K. Calculate the mass of silver in this sample. (6 points)

Answer 1

a)

the molar mass of silver is needed to calculate the molar heat capacity.

molar heat capacity = [heat capacity(in J.g-1.oC-1) / molar mass in (g.mol-1)]

b) energy required = m.c.(delta T)

where m is mass, c is heat capacity and delta T is temperature difference

so, heat/energy required = 245 g * 0.24 J.g-1.K-1 * (373-273) K

= 5880 Joules

= 5.88 kJ

c) using the same formula from (part b)

65 kJ = 65000 J

65000 J = m * 0.24 J.g-1.K-1 * (363-298)K

hence, m = 65000/(0.24*65) grams

m = 4166.67 grams = 4.167 kg