How much heat is required to convert 10g10g of ice at -10^@C10C into steam at 100^@C100C?

1 Answer
Apr 10, 2017

73007300 calories

Explanation:

When 10g10g of ice at -20°C s being converted into steam at 100°C, there are four stages.

  1. Ice at -20°C to ice at 0°C - here it continues to be in the same state i.e. ice and hence heat required is "mass"xx"specific heat"xx"change in temperature" Specific heat for ice is 0.5 cal/g-°C.
  2. Then from ice at 0°C to water at 0°C and heat required is "mass"xx"latent heat", this latent heat required is for conversion of each unit mass of substance. From ice to water it is 80"cal per gram"
  3. Water at 0°C to water at 100°C - here it continues to be in the same state i.e. water and hence heat required is "mass"xx"specific heat"xx"change in temperature" Specific heat for water is 1 cal/g-°C.
  4. Then from water at 100°C to steam at 100°C and heat required is "mass"xx"latent heat", this latent heat required is for conversion of each unit mass of substance. From water to steam, it is 540"cal per gram"

Hence, to find heat is required to convert 10g of ice at -20°C into steam at 100°C,

first calculate heat required to convert 10g of ice at -20°C to ice at 0°C. As specific heat of ice is 0.5"cal/g°C", this is

10xx20xx0.5=100 cal.

heat required to convert 10g of ice to 10g of water at 0°C is

10xx80=800 cal - as latent heat is 80"cal/g"

heat required to convert 10g of water at 0°C to 10g of water at 100°C is

10xx100x1=1000 cal

heat required to convert 10g of water at 1000°C to 10g of steam at 100°C is

10xx540=5400 cal - as latent heat is 540"cal/g"

Hence, total heat required is 100+800+1000+5400=7300 calories