I would say d but I’m not sure
When it changes phases energy is needednto break down the bonds so that is can change state from one phase to another.
From the calculation, the concentration in parts per billion is 6 ppb.
<h3>What is ppb?</h3>
The term ppb refers to the concentration of a substance in parts per billion. We obtain the ppb using the formula;
Mass of solute/ Mass of solution * 10^9
Now, 1L = 1000cm^3 = 1000 g
The concertation in ppb = 6 * 10^-6 g/1000 g * 10^9
= 6 ppb
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