Question

A backpacker collects snow at 0°C, and places it in a cooking pot on a camp stove. It takes 643 kJ of heat energy to melt the snow and bring the water to boiling. Assuming no heat loss, and neglecting the specific heat capacity of the pot, calculate the mass of snow that the backpacker collected. (The specific heat capacity of liquid water, cp = 4.18 J/gK; and: H2O(s)  H2O(l) H = Fusion = 6.02 kJ/mol)

Answer 1

99.88 or 100g

Step-by-step explanation:

The heat required to melt the snow to water and rise it boiling point we consider

1. The heat required to convert the snow to water at the same temperature. This heat is referred to as latent heat of fusion given as

H= mass of the snow or ice (m) x specific latent heat of fusion of ice (l) = ml

2. The heat required to rise the water temperature to it's boiling point

Given by

H= mass of water x specific heat capacity of water x change in temperature = mc(T2-T1)

That give

H= ml+mc(T2-T1)

making m subject of formula gives

H= m(l+c(T2-T1))

H=643KJ, l=6.02KJ/mol, c=4.18J/g, T1=0,T2=100

Substituting values

643*1000= m(6.02*1000+4.18*(100-0))

643000=m(6438)

dividing both side by 6438 give

m= 99.88 or 100g