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. (Data: specific heat capacity of liquid water, c = 4.18 J/g⋅K; and: H2O(s) → H2O(l) ΔH = ΔHfusion = 6.02 kJ/mol)

Answer 1

Answer:

mass (m) of the snow that the backpacker collected= 0.855 kg

Explanation:

Given that:

Q = 643 kJ = 643000 J

ΔHfusion = 6.02 kJ/mol = 6020 J/mol

number of mole of water H2O = $\frac{mass (m)}{18}$

c = 4.18 J/g⋅K

ΔT = 100 K

Since there is a phase change from solid to liquid; then :

$Q =$ $Q_s + Q_l$

ΔH = $\frac{q}{mol}$

However without the given mass; we substitute $\frac{m}{18}$ for the number of moles; so:

Q = $\delta H * \frac{m}{18}$ $+ m*c * \delta T$

$643000 =$$6020 * \frac{m}{18}+ m * 4.18 * 100$

m = 855 g

m = 0.855 kg

mass (m) of the snow that the backpacker collected= 0.855 kg