Explanation

Explanation

To find the time it takes to decay 75% of the initial amount, we need to find the time it takes for 25% of the initial amount to remain.

Since the half-life is 4.5 × 10^9 years, after one half-life, 50% of the initial amount remains.

After two half-lives, 25% of the initial amount remains (50% of 50%).

Therefore, the time it takes to decay 75% of the initial amount is:

2 × half-life = 2 × 4.5 × 10^9 years = 9 × 10^9 years

Explanation

To find the increase in internal energy, we can use the equation:

ΔU = Q - W

where ΔU is the change in internal energy, Q is the heat energy added (which is the latent heat of vaporization in this case), and W is the work done.

Given:

Q = 2240 J (latent heat of vaporization of water per gram)

W = 168 J (work done in the process of vaporization)

Now, we can plug in the values:

ΔU = Q - W

= 2240 J - 168 J

= 2072 J

Explanation

Explanation

Explanation

Explanation

Explanation

Explanation

Explanation