Answer:
The compound has a molar mass of 78.4 g/mol
Explanation:
Step 1: data given
Mass of a sample = 0.5 grams
Mass of benzene = 25 grams
Freezing poing = 5 °C
Kf of benzene = 5.1 °C/m
Freezing point solution = 3.7 °C
Step 2: Calculate molality
ΔT = i*Kf*m
⇒with ΔT = the freezing point depression = 5.0 - 3.7 = 1.3 °C
⇒with i = the can't hoff factor = 1
⇒with Kf = the freezing point depression constant of benzene = 5.1 °C/m
⇒with m = the molality
1.3 = 5.1 * m
m = 1.3 / 5.1
m = 0.255 moles /kg
Step 3: Calculate moles
Molality = moles / mass benzene
0.255 molal = moles / 0.025 kg
Moles = 0.255 molal * 0.025 kg
Moles = 0.006375 moles
Step 4: Calculate molar mass of the compound
Molar mass compund = mass / moles
Molar mass compound = 0.5 grams / 0.006375 moles
Molar mass compound = 78.4 g/mol
The compound has a molar mass of 78.4 g/mol
We shall consider V, the volume and T, the temperature.
According to Boyle's Laws:

In our case:
Answer:
C. Particle size
Explanation:
The sand, which has smaller particles, will go through the sieve, while the rice (with a larger particle size) will not
The answer for the following problem is mentioned below.
- <u><em>Therefore the final volume of the gas is 52.7 ml.</em></u>
Explanation:
Given:
Initial pressure (
) = 290 kPa
Final pressure (
) = 104 kPa
Initial volume (
) = 18.9 ml
To find:
Final volume (
)
We know;
From the ideal gas equation;
P × V = n × R × T
where;
P represents the pressure of the gas
V represents the volume of gas
n represents the no of the moles
R represents the universal gas constant
T represents the temperature of the gas
So;
P × V = constant
P ∝ 
From the above equation;

represents the initial pressure of the gas
represents the final pressure of the gas
represents the initial volume of the gas
represents the final volume of the gas
Substituting the values of the above equation;
= 
= 52.7 ml
<u><em>Therefore the final volume of the gas is 52.7 ml.</em></u>