# The density of platinum is 21.5 g/cm^3 at 25°C. What is the volume of 79.5 g of platinum at this temperature?

Feb 15, 2016

The $V o l u m e$ of platninum @ ${25}^{o} C$ is $3.70 c {m}^{3}$

#### Explanation:

$G i v e n D a t a :$

$D e n s i t y = 21.5 \frac{g}{c {m}^{3}}$
$M a s s = 79.5 g$

$R e q u i red :$ Volume = ?

$S o l u t i o n :$

From the formula
$D e n s i t y = \frac{M a s s}{V o l u m e}$; rearrange to find the volume
$V o l u m e = \frac{M a s s}{D e n s i t y}$; plug in the given data
Volume=(79.5cancelg)/(21.5cancelg/(cm^3)
$V o l u m e = 3.70 c {m}^{3}$

$A n s w e r :$ $3.70 c {m}^{3}$

Feb 15, 2016

Approx. $4$ $c {m}^{3}$.

#### Explanation:

Density, $\rho$, is simply mass per unit volume, and has units $g \cdot c {m}^{-} 3$. So if mass is divided by density, we should get an answer in $\frac{1}{c {m}^{-} 3}$, i.e. in $c {m}^{3}$.

So, $\rho$ $=$ $\text{Mass"/"Volume}$; likewise, $V o l u m e$ $=$ $\frac{\text{Mass}}{\rho}$:

$\text{Volume}$ $=$ $\frac{79.5 \cdot \cancel{g}}{21.5 \cdot \cancel{g} \cdot c {m}^{-} 3}$ $=$ ?? $c {m}^{3}$.