# Question ac840

Aug 17, 2017

$\text{m}$ $= 1.98$ $\text{kg}$

#### Explanation:

Yes you can.

The formula for density is rho = frac("m")("V"); where $\rho$ is the density, $\text{m}$ is the mass, and $\text{V}$ is the volume.

Let's substitute the relevant values into the equation:

$R i g h t a r r o w 0.793$ "kg L"^(- 1) = frac("m")(2.5 " L")

$R i g h t a r r o w 0.793$ ${\text{kg L}}^{- 1} \times 2.5$ "L" = frac("m")(2.5 " L") times 2.5# $\text{L}$

$R i g h t a r r o w 1.9825$ $\text{kg}$ $=$ $\text{m}$

$\therefore$ $\text{m} = 1.98$ $\text{kg}$

Therefore, the mass of solute is $1.98$ $\text{kg}$.

Aug 17, 2017

The mass of solute is $\text{2.0 kg}$.

Refer to the explanation for the process.

#### Explanation:

Another way of expressing the density formula is:

$D = \frac{M}{V}$, where D is density, M is mass, and V is volume.

(It doesn't hurt to know that the Greek lowercase letter rho, $\rho$, is a symbol for density. The Latin D is also acceptable.)

The question gives volume and density, and asks for the mass, which is unknown.

Solution

Rearrange the density formula to isolate $M$. Plug in the known values and solve.

$M = D \times V$

$M = \text{0.793 kg"/color(red)cancel(color(black)("L"))xx2.5color(red)cancel(color(black)("L"))="2.0 kg}$ (rounded to two significant figures due to 2.5 L)