A student dissolves of 18.0 g urea in 200.0 mL of a solvent with a density of 0.95 g/mL . The student notices that the volume of the solvent does not change when the urea dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to significant digits.

Answer:

The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.

Explanation:

Moles of urea = $\frac{18.0 g}{60 g/mol}=0.3 mol$

Volume of the solution = 200.0 mL = 0.2 L (1 mL = 0.001 L)

$Molarity(M)=\frac{\text{Moles of compound}}{\text{Volume of solution in L}}$

Molarity of the urea solution ;

$M=\frac{0.3 mol}{0.200 L}=1.50 M$

Mass of solvent = m

Volume of solvent = V = 200.0 mL

Density of the urea = d = 0.95 g/mL

$m=d\times V=0.95 g/mL\times 200.0 mL=190 g$

$m = 190 g = 190 \times 0.001 kg = 0.19 kg$

(1 g = 0.001 kg)

Molality of the urea solution ;

$Molality(m)=\frac{\text{Moles of compound}}{\text{Mass of solvent in kg}}$

$m=\frac{0.3 mol}{0.19 kg}=1.58 m$

The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.

7 0

3 years ago

Ice Station Bravo near the North Pole launched a helium-filled balloon to check atmospheric conditions. At sea level (1.0 atm) w

Reika [66]

Answer:

12.9 m³ is the new volume

Explanation:

As the temperature keeps on constant, and the moles of the gas remains constant too, if we decrease the pressure, the volume will increase. If the volume is decreased, pressure will be higher.

The relation is this: P₁ . V₁ = P₂ . V₂

1 atm . 0.93m³ = 0.072 atm . V₂

0.93m³ .atm / 0.072 atm = V₂

V₂ = 12.9 m³

In conclusion and as we said, pressure has highly decreased so volume has highly increased.

8 0

3 years ago

What happens to gas particles when they are compressed?

Anuta_ua [19.1K]

Answer:

3)Some gas molecules move further apart and some move closer together.

Explanation:

because When more gas particles enter a container, there is less space for the particles to spread out, and they become compressed. The particles exert more force on the interior volume of the container. This force is called pressure. There are several units used to express pressure.

4 0

3 years ago

A fish tank measures 0.40 meter long by 0.20 meter wide by 0.30 meter high. What is the width of the tank in centimeters?

umka21 [38]

Well the width is 0.20 meters. Since there are a hundred centimeters in a meter, we just have to move the decimal point two times to the right to get a 20 centimeter width.

6 0

3 years ago