What is the weight to volume $ppm$ of $0.05 \% w/v$ $CaCl_2$ aqueous solution?

If $22 \ g$ of benzene $(C_6H_6)$ is dissolved in $122 \ g$ of carbon tetrachloride $(CCl_4)$,calculate the mass percentage of benzene. (in $\%$)

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.

The molality of a solution is defined as:

$250 \, mL$ of a sodium carbonate solution contains $2.65 \, g$ of $Na_2CO_3$. If $10 \, mL$ of this solution is diluted to $1 \, L$,what is the concentration of the resultant solution? (Molecular weight of $Na_2CO_3 = 106$)

$A$ litre of seawater (which weighs $1030 \ g$) contains $6 \times 10^{-3} \ g$ of dissolved oxygen. The concentration of dissolved oxygen in $ppm$ is: