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Answer 1 · 2017-08-17T19:12:06

$"m"$ $= 1.98$ $"kg"$

Yes you can.

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

Let's substitute the relevant values into the equation:

$Rightarrow 0.793$ $"kg L"^(- 1) = frac("m")(2.5 " L")$

$Rightarrow 0.793$ $"kg L"^(- 1) times 2.5$ $"L" = frac("m")(2.5 " L") times 2.5$ $"L"$

$Rightarrow 1.9825$ $"kg"$ $=$ $"m"$

$therefore$ $"m" = 1.98$ $"kg"$

Therefore, the mass of solute is $1.98$ $"kg"$ .

Answer 2 · 2017-08-17T23:01:31

The mass of solute is $"2.0 kg"$ .

Refer to the explanation for the process.

Another way of expressing the density formula is:

$D=M/V$ , 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.

$M=DxxV$

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