Question aa335

Jul 16, 2017

3.99%

Explanation:

NOTE: I'll assume you mean sodium chloride, $\text{NaCl}$, instead of $\text{NaC}$.

We're asked to find the percent by mass of $\text{NaCl}$ in a solution.

We can use the equation

%"mass" = "mass solute"/"mass solution" xx 100%

We're given the mass of the solute is $4.35$ $\text{g}$, so we need to find the mass of the solution, which is

"mass solution" = overbrace(4.35color(white)(l)"g")^"mass of NaCl" + overbrace(105color(white)(l)"g")^"mass of water" = color(red)(109 color(red)("g" (obeying significant figure rules)

We therefore have

%"mass NaCl" = (4.35color(white)(l)"g NaCl")/(color(red)(109color(white)(l)"g soln")) xx 100% = color(blue)(3.99%#