Answer:
b. The final state of the substance is a gas.
d. The sample is initially a liquid. One or more phase changes will occur.
Explanation:
Methane has the following properties:
- Normal melting point: 90.7 K
- Normal boiling point: 111.65 K
*"Normal" refers to normal pressure (1 atm).
According to this, we can affirm:
- Below 90.7 K, methane is solid.
- Between 90.7 K and 111.65 K, methane is liquid.
- Above 111.65 K, methane is gas.
<em>A sample of methane at a pressure of 1.00 atm and a temperature of 93.1 K is heated at constant pressure to a temperature of 158 K. Which of the following are true? Choose all that apply.</em>
<em>a. The liquid initially present will solidify.</em> FALSE. The liquid will vaporize.
<em>b. The final state of the substance is a gas.</em> TRUE.
<em>c. The sample is initially a solid.</em> FALSE. The sample is initially a liquid.
<em>d. The sample is initially a liquid. One or more phase changes will occur. </em>TRUE.
Answer:
P2 = 352 mm Hg (rounded to three significant figures)
Explanation:
PV = nRT
where P is the pressure,
V is the volume,
n is the moles of gas,
R is the gas constant,
and T is the temperature.
We must relate this equation to a sample of gas at two different volumes however. Looking at the equation, we can relate the change in volume by:
P1V1 = P2V2
where P1 is the initial pressure,
V1 is the initial volume,
P2 is the final pressure,
and V2 is the final volume.
Looking at this relationship, pressure and volume have an indirect relationship; when one goes up, the other goes down. In that case, we can use this equation to solve for the new pressure.
P1V1 = P2V2
(759 mm Hg)(1.04 L) = P2(2.24 L)
P2 = 352 mm Hg (rounded to three significant figures)
<u>Answer:</u> The mass of sucrose required is 69.08 g
<u>Explanation:</u>
To calculate the concentration of solute, we use the equation for osmotic pressure, which is:
Or,
where,
= osmotic pressure of the solution = 8.80 atm
i = Van't hoff factor = 1 (for non-electrolytes)
Mass of solute (sucrose) = ?
Molar mass of sucrose = 342.3 g/mol
Volume of solution = 564 mL (Density of water = 1 g/mL)
R = Gas constant = 
T = Temperature of the solution = 290 K
Putting values in above equation, we get:
Hence, the mass of sucrose required is 69.08 g
