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100

True or false: the larger the mass of a gas particle, the lower the average kinetic energy

False. Depends on temperature. Same temp = same average KE

100

A non-reactive salt is added to a beaker saturated with CdS. How will the solubility of CdS(s) change?

Salt will dissolve but not react = shields ions = solubility increases
100

How many atoms are in an FCC unit cell?

4

100
The valves on the apparatus (see slideshow) are opened and the gases mix at constant temperature. What is the distribution of atoms in each container?

7 particles / container

200

How does the BP of CH3CH2CH2CH2OH compare to that of CH3CH2OH? 

BP of CH3CH2CH2CH2OH is higher. 

200

∆Hsoln for CdS(s) in water is positive. What does that say about the relative magnitudes of the three values (∆Hsolute, ∆Hsolvent, and ∆Hmix) comprising ∆Hsoln?

∆Hsolute & ∆Hsolvent = positive; ∆Hmix = negative

(Takes energy to break IMFs in solvent and solute. IMFs coming together in mixture gives off energy.)

200

The density of metals ranges from ____ to ____ g/cm3

1 to 24 (this is useful for doing quick sanity checks on density calculations!)

200

Which gas (see slideshow) has the smallest Henry's constant?

Green

300

The Van der Waals Equation has a and b factors. What does each factor correct?

a corrects for particle-particle interactions. b corrects for size.

300

A 100.0 mg sample of an unknown molecular compound that is NOT an electrolyte is dissolved in 1.00 g of benzene. The freezing point of benzene was depressed by 1.75 °C after the addition. Calculate the molar mass of the unknown compound. (Kf = 4.90 °C/m for benzene)

280 g

300
What kind of semiconductor is produced if germanium is doped with gallium?

p-type

300

Based on the unit cell (see picture), what is the formula for SrxTiyOz?

Sr (x) = 1

Ti (y) = 1

O (m) = 3

400

The reaction 2 X(g) → X2 (g) occurs at STP using 2.1 moles of X(g) in a balloon, which has an initial volume of 10.5 L. Calculate the final volume of the balloon at the end of the reaction. 

Final volume = 5.3 L

400

The concentration of solutes inside a red blood cell is approximately 0.30 M. Calculate the osmotic pressure at 25 °C of red blood cells across the cell membrane from pure water. 

pi = 7.3

400

Generally, metals are malleable and ductile whereas ionic solids are brittle. Explain this difference based on the bonding within each class of materials.

Metallic bonding = "sea of electrons" = can slide. Shifting lattice in ionic solids will cause electrostatic repulsions = brittle. 

400

Based on the phase diagram for sulfur (see slideshow), we see that sulfur has two distinct solid phases: rhombic and monoclinic. With which phase(s) can the rhombic phase exist in direct equilibrium?

Monoclinic, liquid, gas

500

2.5 moles of CO2(g) is placed in a 4.0 L rigid, air-filled (Pair = 1.002 atm) container at 25 °C. Accurately calculate the pressure inside the container after the CO2(g) is introduced. 

15.310 atm (plug into Van der Waals equation for pressure of CO2(g). a = 3.59 L2*atm/mol2. b = 0.0427 L/mol. Then add to pressure of just air.)

500

∆Hvap for water is 40.7 kJ/mol. The atmospheric pressure on Mount Everst is about 0.35 atm. What would the boiling point of water be at the summit of Mount Everest? 

72.35 °C (plug into Clausius-Clapeyron equation and solve)

500

ZnS(s) has a band gap with an energy that corresponds to 350.6 nm light. If the ZnS(s) is doped to make a n-type semiconductor, how will the wavelength of light needed to excite electrons change?

Increase (less energy needed = longer wavelength)

500

What is the formula for this superconductor?

YBa2Cu3O8