Ions have an extra or lost an electron. Isotopes have different numbers of neutrons.
In general when you heat up a liquid such as water its volume "increases" as the heat energy causes the water molecules to move leading to more space between molecules causing it to occupy a larger volume.
hope that helps
<span>let x=gallons of current mixture to be drained
and replaced with pure antifreeze.
4-x=gallons of current mixture remaining in the car.</span>
<span>
0.15(4-x)+1.00x=0.50 x 4
0.6-.15x+x=2
0.85x=1.4
x=1.4/0.85 =1.65 gal
Thus, 1.65 gallons of current mixture to be drained and replaced with pure
antifreeze.</span>
