Practice Test 2
Please attempt this test only after you finish studying for the test. Treat it as a real
exam so you can have a better feel of which areas you need to review further.
1.
A 250.0 mL sample of oxygen gas was collected at 21 C and 785 mm Hg. The next day,
t he temperature rose to 37 C and the pressure was 102.6 kPa . What is the new volume
of the gas?
(101.3 kPa = 1 atm). Answer: 2.7 x 102 mL
2.
Predict whether the substances below will be most miscible in CCl4 or methanol
(CH3OH): Answer in last page. Attempt before checking answer.
A.
B.
C.
D.
E.
F.
NH3
CH3CH2CH2CH2CH2CH2CH2CH3
CO2
I2
BF3
C2H5OH (ethyl alcohol)
3.
A sample of hydrogen gas has a volume of 8.56 L at a temperature of 0 C
and a pressure of 1.5 atm. Calculate the moles of hydrogen gas present in
this gas sample. Answer: 0.57 moles
4.
How many liters of gas is 14.0 g of chlorine at 300.0 K and 1.51 atm? Answer: 3.22 L
5.
A gas with the formula C7H16O) is burned in air. When the equation is balanced using
smallest whole numbers, determine the sum of the coefficients for the overall process.
Answer: 53
6.
A 9.00 M solution HNO3 of unknown volume is diluted to make 6.50 L of a 1.25 M
solution.
A.
Determine the volume of the 9.00 M solution needed for the dilution.
B.
How much water must be added to the 9.00 M solution in order to make
the dilution? (Answer: A. 0.903 L ; B. 6.50 – 0.903 = 5.60 L of water is
added to 0.903 L of 9.00 M nitric acid to make 6.50 L of 1.25 M
solution)
7.
Which acids and bases are strong electrolytes? (strong acids and bases: know those on
page 25) Which ones are weak electrolytes? (weak acids and bases: know those on page
25 plus ammonia is a weak base and acetic acid, carbonic acid, and phosphoric acid are
weak acids).
8.
Consider the Haber Process for the synthesis of ammonia when 30.0 g N2 and 10.0 g H2
react:
N2(g) + H2(g) → NH3(g)
A. Balance this equation.
B. Determine the mass of ammonia formed in this reaction. (answer: 36.5 g
ammonia)
C. Determine the percent yield of the reaction if 32.1 g of the product is obtained.
Answer: 87.9%
9.
Know how to rank compounds in order of increasing B.P, increasing intermolecular
forces of attraction, vapor pressure. See Examples in old exams.
10.
Characteristics of the kinetic molecular theory and behavior of ideal gases: page 16 and
page 17.
11.
If you have a 30% discount coupon in Kohls, what does this mean in $/$ units? Answer:
$30 off for every $100. So if an item costs a $100, you pay $70. Similarly, what does a
30% by mass of NaCl in a solution mean? Answer: 30 g NaCl in 100 g of the solution.
12.
Calculate the pH and pOH given H+ or OH- ion concentration. Similar to page 26 in
course guide. Also see more examples in old exams.
13.
What are the intermolecular forces of attraction that exists in these molecules:
A.
Br
B.
C2H5OH
C.
HF
D.
NH3
E.
HCl
F.
H2S
These are just some examples. You should know how to figure this out with any
molecule or atom.
16.
How many grams of glucose are there in 100 mL of a 0.278 M glucose solution?
Answer: 5.00 g
17.
Calculate the molarity of glucose solution formed from dissolving 5.00 g glucose in
sufficient water to form 100. mL of solution. Answer: 0.278 M
18.
How many total number of N atoms are present in 20. g of N2O4.(answer: 2.6 x 1023
atoms) Method: g N2O4 to moles of N2O4 to molecules of N2O4 to atoms of N
19.
Relationship between intermolecular forces and Vapor Pressure, Surface Tension, and
Boiling Point.
20.
How does vapor pressure affect volatility of compounds? Look at old exams for
questions like this. Answer: High V.P means high volatility and low intermolecular
force of attraction. So look at compounds given and be able to say if the molecule
has a low intermolecular force or high I.M force of attraction. For molecules with
the same types of intermolecular forces of attraction, volatility is determined by the
size. Smaller the molecule, more the volatility. Example: which is more volatile:
CCl4 or CBr4 Answer is CCl4
21.
Examples for Boyles Law, Charles Law, and Gay-Lussac’s Law and explain how these
examples obey the laws.
22.
Example of buffers in the body. Also know the most important buffer in the body.
23.
Blood pressure table on page 20 and application to blood pressure on page 20.
24.
A patient requires 0.60 g of antibiotic over a 24 hour period. How many mL of a 1.0%
(w/v) antibiotic solution must be given? Answer: 60.0 mL
25.
A topical antibiotic is 1.0% (w/v) clindamycin. How many grams of clindamycin are in
60.0 mL of the 1.0% (w/v) solution? Answer: 0.60 g
26.
A 0.50 L bottle of wine contains 60. mL of ethanol. What is the % composition (v/v) of
ethanol in this aqueous solution? Answer: 12%
27.
Titration problems. Practice problems on page 27 and in lab 8
28.
Single displacement and double displacement reactions and writing net ionic equations
where required. Labs 4 and 5 and pages 7 and 8 in course guide.
29.
Define/explain:
Buffer solution, electrolyte, nonelectrolyte, vapor pressure, surface tension, acids, bases,
dynamic equilibrium, polarizability, hydrogen bonding, dipole-dipole forces, acidosis,
alkalosis, systolic, and diastolic.
30.
Calculate the number of chromium atoms in 78.82 g of K2Cr2O7. (answer: 3.227 x 1023
Cr atoms)
31.
Indicator used in titration and the results with acids and bases.
ANSWERS:
2.
Predict whether the substances below will be most miscible in CCl4 or methanol
(CH3OH): See if molecule is polar or nonpolar first and next if it forms hydrogen bonds
like water or methanol. Remember: “Like dissolves like”!
A.
B.
C.
D.
E.
F.
13.
NH3 polar from lewis structure (trigonal pyramidal) and hydrogen
bonding like water which is polar. So soluble in methanol
CH3CH2CH2CH2CH2CH2CH2CH3 nonpolar so soluble in CCl4
CO2 nonpolar so soluble in CCl4
I2 nonpolar so soluble in CCl4
BF3 nonpolar so soluble in CCl4
C2H5OH (ethyl alcohol) polar soluble in methanol
What are the intermolecular forces of attraction that exists in these molecules:
A.
B.
C.
D.
E.
F.
Br2 : LDF
C2H5OH : LDF, dipole, hydrogen bonding
HF: LDF, dipole, hydrogen bonding
NH3: LDF, dipole, hydrogen bonding
HCl: LDF, dipole
H2S: LDF, dipole