Calculate the molarity of $NaOH$ solution prepared by dissolving $0.4 \ g$ of $NaOH$ in enough water to form $500 \ mL$ of the solution. (in $M$)

Which unit of concentration value does not change with change in temperature?

If the concentration of glucose $(C_{6}H_{12}O_{6})$ in blood is $0.72 \ g \ L^{-1}$,the molarity of glucose in blood is $..... \times 10^{-3} \ M$. (Nearest integer)
(Given: Atomic mass of $C=12, H=1, O=16 \ u$)

What is the molarity of acid in vinegar containing $4.0 \%$ acetic acid by $(w/w)$ and having a density of $1.02 \ g/mL$ (in $M$)?

If $80 \ g$ of $NaOH$ is mixed with $54 \ g$ of water to form a solution,calculate the mole fraction of water.

Explain parts per million (ppm) in brief.