The $\% \ w/V$ unit is used in which branch of science?

What mass of ethanol in $g$ must be added to $1.0 \, kg$ of water to have a mole fraction of ethanol equal to $0.2$?

The concentration of $Ca^{2+}$ ions in a water sample is $0.0002 \ M$. What is the concentration of $Ca^{2+}$ in $ppm$ by weight-volume?

To prepare a solution of concentration $0.03 \ g/mL$ of $AgNO_3$,what amount of $AgNO_3$ should be added in $60 \ mL$ of solution?

The number of units,which are used to express the concentration of solutions from the following,is $.......$ Mass percent,Mole,Mole fraction,Molarity,ppm,Molality.

For a solution containing $0.03659 \ g/mL$ of $HCl$ and a solution containing $0.04509 \ g/mL$ of acetic acid $(CH_3COOH)$,which of the following is true?