Question

11. + -/1.5 points How many Joules of heat are required to raise the temperature of 13 g of aluminum from 23 °C to 55 °C?! 12. +-/1.5 points How many kilocalories of heat are required to evaporate 1.13 kg of water that is initially at 100.0 °C? kcal 13. +-/1.6 points How many Joules of heat are required to melt 0.21 kg of silver that is initially at 27 °C ? (Csilver = 240 , L-silver = 1.05 x 105 the melting point of silver is 962 °C)

please answee as much questions are you can greatly appredcited

Answer 1

Ans 11 :

Heat = mass x specific heat x change in temperature

mass = 13 g

specific heat = 0.900 J/g^oC

putting values :

Heat = 13 g x 0.900 J/g^oC x (55^oC - 23^oC)

= 374.4 J

Ans 12 :

Heat of vaporization of water = 539.2 kcal/kg

so here heat required :

= heat of vap x mass (kg)

putting values :

= 539.2 kcal/kg x 1.13 kg

= 609.3 kcal

Ans 13 :

Heat required to raise the temperature of silver to 962^oC :

= mass x specific heat x change in temperature

putting values :

= 0.21 kg x 240 J/kg^oC x (962^oC x 27^oC)

= 47124 J

heat required to melt :

= mass x Lf-silver

putting values :

= 0.21 kg x 1.05 x 10⁵J/kg

= 22050 J

so total heat = 47124 J + 22050 J

= 69174 J