Question

chemistry: density problems
for each problem below, write the equation and show your work. always use units and box in your final answer.
1 the density of silver (ag) is 10.5 g/cm³. find the mass of ag that occupies 965 cm³ of space.
2 a 2.75 kg sample of a substance occupies a volume of 250.0 cm³. find its density in g/cm³
3 under certain conditions, oxygen gas (o₂) has a density of 0.00134 g/ml. find the volume occupied by 250.0 g of o₂ under the same conditions.
4 find the volume that 36.2 g of carbon tetrachloride (ccl₄) will occupy if it has a density of 1.60 g/ml.
5 the density of ethanol is 0.789 g/ml at 20°c. find the mass of a sample of ethanol that has a volume of 150.0 ml at this temperature.
6 30.0 g of each of the following acids are needed. find the volume of each that must be measured out in a graduated cylinder.
a hydrochloric acid (hcl), density = 1.184 g/ml
b sulfuric acid (h₂so₄), density = 1.834 g/ml
c nitric acid (hno₃), density = 1.251 g/ml

Explanation:

1.

Step1: Recall density formula

The density formula is $
ho=\frac{m}{V}$, where $
ho$ is density, $m$ is mass and $V$ is volume. We can re - arrange it to find mass $m =
ho V$. Given $
ho = 10.5\ g/cm^{3}$ and $V=965\ cm^{3}$.
$m=
ho V=10.5\ g/cm^{3}\times965\ cm^{3}=10132.5\ g$

Step1: Convert mass to grams

First, convert the mass from kg to g. Since $1\ kg = 1000\ g$, a $2.76\ kg$ sample has a mass $m = 2.76\times1000\ g=2760\ g$.

Step2: Calculate density

Using the density formula $
ho=\frac{m}{V}$, with $m = 2760\ g$ and $V = 250.0\ cm^{3}$, we have $
ho=\frac{2760\ g}{250.0\ cm^{3}}=11.04\ g/cm^{3}$

Step1: Rearrange density formula for volume

From $
ho=\frac{m}{V}$, we can get $V=\frac{m}{
ho}$. Given $m = 250.0\ g$ and $
ho=0.00134\ g/mL$.
$V=\frac{m}{
ho}=\frac{250.0\ g}{0.00134\ g/mL}\approx186567.16\ mL$

Answer:

$10132.5\ g$

2.