Answer:
Solute - The solute is the substance that is being dissolved by another substance. In the example above, the salt is the solute. Solvent - The solvent is the substance that dissolves the other substance. In the example above, the water is the solvent.
Explanation:
1.0 mole ---------- 6.02x10²³ molecules
4.5 moles -------- ?
4.5 * 6,02x10²³ / 1.0
= 2.709x10²⁴ molecules units
The mass decay rate is of the form

where
m₀ = 3000 g,the initial mass
k = the decay constant
t = time, years.
Because the half-life is 30 years, therefore

After 60 years, the mass remaining is

Answer: 750 g
<span>I think the correct answer is A. A
buffer is a substance that resists small change in the acidity of a solution
when an acid or base is added to the solution. Usually, a buffer involves a
weak acid or a weak alkali and one of its salt.</span>