Question

Hey yall, Im working on a quiz I completed. I really need to get a 100 I worked all the problems out and i was wondering if one of yall would mind checking it for me. If i missed one if yall could tell me how to get the correct answer?

1.The intermolecular forces present in CH3NH2 include which of the following?
I. dipole-dipole
II. ion-dipole
III. dispersion
IV. hydrogen bonding
ANS: I, III, and IV


2. A liquid boils when its
ANS: vapor pressure is equal to, or greater than, the external pressure pushing on it.
- I was actually torn between picking this answer choice and "vapor pressure is exactly one atm"...is that wrong?


3. How much energy (heat) is required to convert 52.0 g of ice at –10.0°C to steam at 100°C?

specific heat of ice:	2.09 J/g·°C	ΔHfus = 6.02 kJ/mol
specific heat of water:	4.18 J/g·°C	ΔHvap = 40.7 kJ/mol

specific heat of steam:

1.84 J/g·°C

ANS:157.8 kJ

4. Which of the following liquids would have the highest viscosity at 25°C?

CH3Br

C2H5OH

CH2Cl2

ANS : HOCH2CH2OH

CH3OCH3

5. Which of the following would be expected to have the lowest vapor pressure at room temperature?

ANS: water, bp = 100°C

acetone, bp = 56°C

ethanol, bp = 78°C

methanol, bp = 65°C

6. Given the following liquids and their boiling points, which has the highest vapor pressure at its normal boiling point?

ANS:	The vapor pressure of each of the liquids at its normal boiling point would be the same.

ethanol, bp = 78°C

benzene, bp = 80°C

water, bp = 100°C

methanol, bp = 65°C

7. Which of the following liquids would make a good solvent for iodine, I2?

ANS: CS2

CH3OH

HCl

H2O

NH3

8. What is the boiling point of a solution of 11.0 g of lactose (C12H22O11) in 145.0g of water? (Kb (H2O) = 0.52 °C/m)
ANS: 100.1 deg C

9. Calculate the molality of a 20.0% by mass ammonium sulfate (NH4)2SO4 solution. The density of the solution is 1.117 g/mL.
ANS: 1.89

10. A solution that is 33.6 % by mass of phenol (C6H5OH) in water is prepared. What is the mole fraction of the phenol?

ANS: 0.0883

Answer 1