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

230 kJ

Explanation:

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

where

m is the mass of the substance

is the latent heat of fusion of the substance

In this problem,

m = 10.0 kg is the mass of the lead sample

is the latent heat of fusion of lead

Substituting,

Q = 230 kJ

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

now we know that

here m = 10 kg

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

28. evolution

29. environment, survive, offspring  

explanation: