# Question #ccb82

##### 1 Answer

Here's what I got.

#### Explanation:

The density of the solution can be found by dividing its **total mass** by its **total volume**.

You can safely assume that dissolving **not** change the volume of the solution, so right from the start, you know that

#V_"solution" = V_"water" = "500 mL"#

Now, you know the mass of sodium chloride, which is the *solute*, so you must figure out the mass of the water, which is the *solvent*.

Using the fact that

#color(blue)(ul(color(black)("1 mL" = "1 cm"^3)))#

and that water has a density of

#500 color(red)(cancel(color(black)("mL"))) * (1color(red)(cancel(color(black)("cm"^3))))/(1color(red)(cancel(color(black)("mL")))) * "1 g"/(1color(red)(cancel(color(black)("cm"^3)))) = "500 g"#

Therefore, the **total mass** of the solution will be

#m_"total" = m_"NaCl" + m_"water"#

which in your case is

#m_"total" = "2 g + 500 g"#

#m_"total" = "502 g"#

The **density** of the solution,

#rho_"sol" = m_"total"/V_"solution"#

Plug in your values to find

#rho_ "sol" = "502 g"/"500 mL" = "1.004 g mL"^(-1)#

Now, I'll leave the answer rounded to four **sig figs**, but keep in mind that it **should** be rounded to one **significant figure**.

So the correct answer here would be

#rho_"sol" = "1 g mL"^(-1)#