A piece of ice (heat capacity $= 2100 J k g^{- 1 \circ} C^{- 1}$ $= 2100J kg^(-1 @)C ^-1$ and latent heat $= 3.36 \times 10^{5} J k g^{- 1}$ $= 3.36 xx 10^5 J kg^-1$ ) of mass $m$ $m$ gram is at $- 5^{\circ} C$ $-5^@C$ at atmospheric pressure. It isgiven $420 J$ $420 J$ of heat so that the ice starts melting. Finally when the ..........?

Question

A piece of ice (heat capacity $= 2100 J k g^{- 1 \circ} C^{- 1}$ $= 2100J kg^(-1 @)C ^-1$ and latent heat $= 3.36 \times 10^{5} J k g^{- 1}$ $= 3.36 xx 10^5 J kg^-1$ ) of mass $m$ $m$ gram is at $- 5^{\circ} C$ $-5^@C$ at atmospheric pressure. It isgiven $420 J$ $420 J$ of heat so that the ice starts melting. Finally when the ice-water mixture is in equilibrium, it is found that $1 g$ $1 g$ of ice has melted. Assuming there is no other exchange in the process, the value of $m$ $m$ is?

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Answer 1 · 2018-05-04T17:31:06

Refer to Explanation

Thermal energy absorbed to heat up the ice to $0^{\circ} C$ $0^@C$ :
$Q=m c Delta theta$
$Q=m/1000 * 2100 * [0-(-5)]$
$Q=(10.5m )J$

Thermal energy absorbed to melt 1g of ice:
$Q=ml_v$
$Q=1/1000 * 3.36xx10^5$
$Q=336J$

$(10.5m)J +336J = 420J$
$:.m=8 g$