Gold has a latent heat fusion of 64.5 j/g. how much energy is required to melt 20.0 g of gold?

The amount of heat require to melt the gold is 1290 J.

Explanation:

Formula:

Q = m × Lf

Q = heat required to melt the substance

m = mass of given substance

Lf = Latent heat of fusion

Given data:

Lf = 64.5 j/g

m = 20 g

Q = ?

Now we will put the values in formula.

Q = m × Lf

Q =  20 g × 64.5 j/g

Q = 1290 J

The amount of heat require to melt the gold is 1290 J.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.