Download Practice Questions

Practice Questions
In addition to the following questions, all on-line Guiding & Embedded Powerpoint questions on the
calendar since the previous exam should be considered as well as those questions in that period’s lab
workheets. The class meeting’s weekly notes are a useful guide as to which topics & information are highly
important.
Which of these chemical processes adds to the carbon footprint?
a. burning fossil fuels
b. cement production
c. flatulence (farting) from food digestion in certain animals
d. breathing in all animals
d. all of the above
Compare the complete combustion of 1 mole of methane CH4 and 1 mole of butane C4H10. Circle all that apply.
CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (g)
2 C4H10 (g) + 13 O2 (g) → 8 CO2 (g) + 10 H2O (g)
The amount of oxygen that is needed for the reaction:
a. is the same for both.
b. is greater for butane.
c. is greater for methane.
The amount of CO2 produced:
a. is the same for both.
b. is greater for butane.
c. is greater for methane.
A given gas has a volume of 55 mL at a pressure of 1.2 atm. What will be its final volume if the pressure is increased to 2.4
atm (Temperature remains constant)?
a.
b.
c.
d.
e.
27.5 mL
33 mL
91.7 mL
110 mL
55 mL
A flexible walled balloon is heated. What happens to its volume? (Pressure remains constant.)
a.
b.
c.
d.
e.
Increases in proportion to the temperature change in Celsius
Decreases in proportion to the temperature change in Celsius
Increases in proportion to the temperature change in Kelvin
Decreases in proportion to the temperature change in Kelvin
Cannot determine
Which gas is not a greenhouse gas?
a.
b.
c.
d.
O2
CH4
CO2
H2O
The lower atmosphere can be best described as being comprised of:
a. Mostly oxygen with all other molecules present in very small amounts.
b. Mostly nitrogen with all other molecules present in very small amounts.
c. Mostly nitrogen and oxygen with more oxygen than nitrogen, and with some other trace molecules.
d. Mostly nitrogen and oxygen with more nitrogen than oxygen, and with some other trace molecules.
The Earth is relatively warm due to
a. Ultraviolet radiation from the sun being absorbed by ozone molecules in the stratosphere.
b. X-rays and gamma rays exciting nitrogen and oxygen gas molecules in the lower atmosphere.
c. Infrared radiation being absorbed by certain trace gas molecules in the lower atmosphere.
d. The very high temperature of the molten inner core of the Earth which is composed mostly of iron.
Not all molecules absorb energy from sunlight. Which of the following does not absorb heat?
a. carbon dioxide
b. oxygen
c. water vapor
d. methane
Without the atmosphere’s natural greenhouse effect, Earth’s temperature at the surface would be:
a. 30-40 oF warmer
b. 50-60 oF cooler
c. the same
A weather balloon is filled with helium to a volume of 10.0 L. What is the volume of the balloon when it rises to an altitude
where the pressure has decreased by 80% (1 atm to 0.2 atm) and the Kelvin temperature decreased by 20% (300 K to 240 K)?
a.
b.
c.
d.
e.
4.0 L
8.0 L
16.0 L
25.0 L
40.0 L
What is occurring to the temperature if the molecules of a gas move more slowly on average?
a. Increases b. Decreases
c. Does not change
d. Cannot determine
What change in pressure occurs when molecules of a gas strike the walls of the container less often?
a. Increases b. Decreases
c. Does not change
d. Cannot determine
What is the correct formula for the compound formed by the combination of the ammonium ion (NH4)1+ ( a weak acid) and
the phosphate ion (PO4)3- (a weak base)?
a.
b.
c.
d.
NH4PO4
NH4(PO4)3
(NH4)3(PO4)2
(NH4)3PO4
Select all of the acids in the following list.
a.
b.
c.
d.
e.
f.
NaOH (aq)
C8H18 (l)
Ba2SO4 (s)
H2SO3(aq)
CH3COOH(aq)
CH3CH2OH (aq)
A solution of unknown content had a pOH of 4.5, which of the following statements is correct
a.
b.
c.
d.
e.
The pH = 7 and the solution is neutral
The pH = 4.5 and the solution is acidic
The pH = 9.5 and the solution is basic
The pH = 14 and the solution is basic
The pH cannot be determined except with litmus paper
In the reaction diagram above, which corresponds to the heat of reaction (ΔHrxn)?
a) B
b) D
c) A
d) C
e) None of the above
In the reaction diagram above, the reaction is:
a)
b)
c)
d)
e)
Isothermic
Eurythermic
Exothermic
Stenothermic
Endothermic
Refer to the following reaction diagram below:
Which of the following statements is true?
a)
b)
c)
d)
The reaction is exothermic.
The reaction is endothermic.
The activation energy is a negative value.
The reaction is neither exothermic nor endothermic.
If an enzyme were added to the reaction, it would
a)
b)
c)
d)
Decrease the rate of reaction.
Increase the Energy of activation Eact
Decrease the Energy of activation Eact
Increase the heat produced ΔH.
A
B
In the equilibrium above, every one minute 20% of reactants A react to form products B while during that
same period of time 80% of the products B react in the opposite direction to form reactants A. This
continues every minute over time.
Equilibrium is reached at the end of :
a)
b)
c)
d)
e)
~ 1 minute
~ 4 minutes
~ 40 minutes
~ 400 minutes
Never
The equilibrium constant K = [Products] / [Reactants] for this reaction is numerically:
a)
b)
c)
d)
0
<1
>1
There is no way to approximate the value.
Which of the following is most important when determining the degree of unsaturation of a fat or an oil?
a)
b)
c)
d)
Number of hydrogen atoms
Number of double bonds
Number of carbon atoms
Number of single bonds
Peptide bonds contain which of the following linkages?
a)
b)
c)
d)
(-CH-)
(-COO-)
(-CONH-)
(-NHHC-)
Of the choices below, which is not found in the photosynthesis reaction?
a)
b)
c)
d)
Glucose (C6H12O6)
Water
Nitrogen
Oxygen
Proteins are natural polymers composed of what monomers?
a)
b)
c)
d)
e)
Amino acids
Carbohydrates
Ethylene
Cholesterol
Amides
TRUE/FALSE:
Earth's lower atmosphere is comprised of a homogeneous mixture of molecules in the gas phase.
Global warming, the long-term increase in world temperatures, occurs mainly because certain man made chemicals thin
the ozone layer, allowing more solar radiation to reach Earth’s surface.
Burning gasoline chemically produces water and carbon dioxide.
The concentration of carbon dioxide in the atmosphere today is significantly higher than at the start of the Industrial
Revolution, around 1750.
Some kinds of particulate pollution in the atmosphere counteract global warming by reducing the solar radiation that
reaches Earth’s surface.
Ocean life is not threatened from the effects of carbon dioxide buildup and climate change.
Scientists can derive evidence of the chemical composition of Earth’s atmosphere and temperature hundreds of
thousands of years ago from ice cores and the gas bubbles trapped in ancient ice.
Consider the following graph:
Earth has been warmer in the past 100,000 years.
Earth has been colder in the past 100,000 years.
Using renewable biofuels like ethanol and biodiesel in place of gasoline will eliminate global warming.
Molecules of different gases having the same volume, the same pressure, and the same temperature will have the same
average kinetic energy.
Molecules of different gases having the same volume, the same pressure, and the same temperature will have the same
average speed.
Molecules of different gases having the same volume, the same pressure, and the same temperature will have an average
speed that is in proportion to their molecular mass.
A balloon containing 22.4 liters of hydrogen gas at zero degrees Celsius and a pressure of one atmosphere will contain the
same number of oxygen atoms in a balloon of the same size at the same pressure and temperature.
A balloon containing 22.4 liters of hydrogen gas and a pressure of one atmosphere is at 25 degrees Celsius. If the
temperature doubles to 50 degrees Celsius, the volume should increase to 24.3 liters; an increase of ~ 8%.
A balloon containing 22.4 liters of hydrogen gas and a pressure of one atmosphere is at 25 degrees Celsius (298 K). If the
temperature doubles to 596 K, the volume should double to 44.8 liters; an increase of 100%.
Compare the complete combustion of 1 mole of methane CH4 and 1 mole of butane C4H10. Circle all that apply.
Leptin is a carbohydrate that is involved with controlling appetite.
Catabolism is the metabolic breakdown of large molecules.
The primary protein structure is defined by alpha helices and beta sheets.
Alpha helices and beta sheets are a result of hydrogen bonding.
In the upper atmosphere, ozone absorbs infrared radiation which causes genetic mutation and skin cancer.
For each of the four reactions, classify the reactants as an acid (A) or a base (B) and the
products as the conjugate acid (CA) or conjugate base (CB).
CN– + H2O → HCN + OH–
NH3 + HCl → NH4+ + Cl
The pH of five solutions were measured: A =1.5; B = 7.0; C = 2.5; D = 8.8; E = 12.1
Which are basic? __________
Which is(are) neutral? ________
Which is the weakest base? _______
Which is the strongest acid? _______
Refer to:
http://chemconnections.org/general/chem106/106assign.html#CO2
http://chemconnections.org/general/chem106/Chem%20106%20Week%2012.2017.ppt.pdf
http://chemconnections.org/general/chem106/Limiting%20Reactant-demo%20wks%202017s.pdf
A set of three flasks with balloons attached were filled with 70.0 mL 1.0 M hydrochloric acid, HCl (aq). Then the balloons
had different amounts of solid sodium bicarbonate added to the acid: 2.00g NaHCO3 (s) added from the green balloon, 4.00g
NaHCO3 (s) added from the yellow balloon, and 6.00g NaHCO3 (s) added from the blue balloon. When mixed, the sodium
bicarbonate reacted with the acid and produced carbon dioxide, which inflated the balloon in the following reaction:
_____ HCl (aq) + ____ NaHCO3(s) _____ CO2(g) + _____ H2O(l) + _____ NaCl(aq)
1.
2.
3.
4.
Balance the above equation.
Identify the limiting reactant in each flask.
Calculate the number of moles of sodium bicarbonate that were added to the respective flasks. (The moles of
hydrochloric acid in all 3 flasks is equal to its molarity (1.0 mol / L) x 70.0 ml x 1.00 L / 1,000. mL)
Calculate the number of moles of CO2 theoretically produced and then calculate the respective theoretical volume of
CO2 produced in each flask assuming STP (Standard Temperature and Pressure) and that 1 mole of gas equals 22.4
liters.
___________________________
The following compound, methylparaben, 4-hydroxybenzoic acid methyl ester, is found in canine estrus secretions.
Remarkably, it is used as a preservative in foods and cosmetics, and it is also an isomer of oil of wintergreen which can be
prepared from salicylic acid, the same starting material used to prepare aspirin.
Name the two functional groups each with one or more oxygen aroms that are present in methylparaben
O
.
COCH3
OH
___________________________
What are the functions in aspirin and its molecular formula? ( CxHyOz)
O
CO-H
O
OCCH3
Bonus: A DVC chemistry student attempted to synthesize 0.500 g of aspirin, but obtained only an 80% yield. If a dose of
325 mg were required, did the student's synthesis provide a sufficient amount for one dose? Show your calculation. (1 g =
1000 mg)
Match with the choices on the right.
O
A) amide
C
H
CH3
B) trans-double bond
O
H3C
C) cis-double bond
CH3
O
D) ether
C
H2NH2C
E) aldehyde
OH
F) ketone
O
H3C
H
C
H2
G) alcohol
O2C-R
H) fatty acid
O2C-R'
I) protein
O2C-R''
H3C
J) starch
H
K) disaccharide
H
CH3
L) amino acid
HO
HO
M) triglyceride
OH
N) carboxylic acid
O
O
O
HO
HO
OH
OH
OH