Gas Laws
A mixture containing 0.477 mol He (g), 0.280 mol Ne (g), and 0.110 mol Ar (g) is confined in a 7.00-L container at 25 °C. What is the partial pressure of the He(g) in units of atm?
1.67 atm
What is the molar mass of an ideal gas which has a density of 1.30 g/L measured at 27°C and 0.400 atm?
80.0 g/mol
On the board what is present at point C, B, A?
Solid, liquid, gas (respectively).
mol solute/ kg solvent, m
What makes a strong electrolyte?
Something that will dissociate in water (i.e. ionic compounds).
A mixture containing 0.477 mol He (g), 0.280 mol Ne (g), and 0.110 mol Ar (g) is confined in a 7.00-L container at 25 °C. What is the total pressure of the gas mixture in the container in units of atm?
3.03 atm
On a sheet of paper, draw a complete and accurate representation of the molecular geometry for carbon dioxide. Using an arrow that begins on the more electropositive atom and ends on the more electroneg atom, show any polar bonds. Describe the geometry.
Must have correct drawing and state the geometry is linear.
What are the intermolecular forces available between sulfur difluoride molecules?
LDF and dipole-diople
Which of the following aqueous solutions would give the highest boiling point? (assume ideal behavior for the solutions).
0.20 m potassium fluoride
0.20 m ethanol (C2H5OH)
0.10 m magnesium nitrate
0.10 m sodium sulfate
KF; i=2 Boiling point elevation, therefore largest i*m will give the biggest number to add to the temperature of the pure solvent.
Is methanol (CH3OH) a good electrolyte? Why or why not?
No, because it will only form hydrogen bonds with water (it will not dissociate).
A 5.0 L air sample at -50 ºC has a pressure of 107 kPa. The temperature is raised to 100 ºC and the volume expands to 7.0 L. What is the new pressure in atm?
1.3 atm
Sulfur difluoride is a polar molecule.
True
Between Carbon dioxide, Methanol and Sulfur difluoride which will have the highest boiling point? Why?
Methanol and because of the h-bonds.
The antifreeze in most automobile radiators is a mixture of equal volumes of ethylene glycol and water, with minor amounts of other additives that prevent corrosion. What are the (a) mole fraction and (b) molality of ethylene glycol, C2H4(OH)2, in a solution prepared from 2.22 ×× 103 g of ethylene glycol and 2.00 ×× 103 g of water (approximately 2 L of glycol and 2 L of water)?
(a) 0.244
(b) 17.9 m
What is the chemical formula for calcium chloride? and show how it interacts with water.
CaCl2, must show separation and interactions with water correctly.
Methane (CH4) is being considered for use as an alternative automotive fuel to replace gasoline. One gallon of gasoline could be replaced by 655 g of CH4. What is the volume of this much methane at 25 °C and 745 torr?
1.02 * 10^3 L
On a sheet of paper, draw a complete and accurate representation of the molecular geometry for methanol (CH3OH). Using an arrow that begins on the more electropositive atom and ends on the more electroneg atom, show any polar bonds. Describe the geometry.
Accurate drawing and tetrahedral.
What does points D and E represent?
Critical point and the Triple point
Calculate the mole fraction of solute and solvent in a 3.0 m solution of sodium chloride.
0.052
Calculate the morality of potassium ions in a 0.185 M solution of potassium carbonate.
0.370 M of K+
When filled with air, a typical scuba tank with a volume of 13.2 L has a pressure of 153 atm. If the water temperature is 27 °C, how many liters of air will such a tank provide to a diver’s lungs at a depth of approximately 70 feet in the ocean where the pressure is 3.13 atm?
667 L
A 10.0-L vessel contains 2.50 × 10−3 mol of H2, 1.00 × 10−3 mol of He, and 3.00 × 10−4 mol of Ne at 35 °C.
(a) What are the partial pressures of each of the gases?
(b) What is the total pressure in atmospheres?
H2 = 6.23 * 10^-3 atm
He = 2.53 * 10^-3 atm
Ne = 7.58 * 10^-4 atm
Pt = 9.61* 10^-3 atm
What is happening in the forward and reverse at points F, G, H?
F: (f) sublimation (r) deposition
G: (f) melting (r) freezing
H: (f) vaporization (r) condensation
Compute the vapor pressure of an ideal solution containing 92.1 g of glycerin, C3H5(OH)3, and 184.4 g of ethanol, C2H5OH, at 40 °C. The vapor pressure of pure ethanol is 0.178 atm at 40 °C. Glycerin is essentially nonvolatile at this temperature.