Question

1. How much heat is needed to melt 10.0 kg of lead at its melting point?

Answer 1

Q = 230 kJ

Step-by-step explanation:

Heat required to melt a given matter at its melting point is given by latent heat of fusion

It will remain constant for a given metal

for lead the latent heat of fusion is given as

`L = 23 kJ/kg`

now we know that

`Q = mL`

here m = 10 kg

so heat required to melt 10 kg of lead is given as

`Q = 10 * 23`

`Q = 230 kJ`

Answer 2

230 kJ

Step-by-step explanation:

The amount of heat needed to melt a substance at its melting point is:

`Q=m\lambda_f`

where

m is the mass of the substance

`\lambda_f` is the latent heat of fusion of the substance

In this problem,

m = 10.0 kg is the mass of the lead sample

`\lambda_f = 23 kJ/kg` is the latent heat of fusion of lead

Substituting,

`Q=(10.0 kg)(23 kJ/kg)=230 kJ`