Chemistry Multiple Choice

1 In which direction will the point of equilibrium shift when a catalyst is added to the following equilibrium system?

KNO3 + 34.7 kJ K+1 (aq) + NO3-1 (aq)

a.Shift to the right
b.Shift to the left
c.No shift

2.The magnitude of Keq depends on
a.Initial concentration of reactants
b.Presence of a catalyst
c.Temperature
d.Volume of reaction vessel

3.In which direction will the point of equilibrium shift when the pressure is decreased in the following equilibrium?

H2 (g) + Cl2 (g) 2 HCl (g)
a.Shift to the right
b.Shift to the left
c.No shift

4.The equilibrium constant can change significantly with a change in
a.Concentration
b.Catalyst
c.Temperature
d.Pressure

5.In the following equilibrium, when sodium ion is removed, the concentration of chloride ion will
Na+1 (aq) + Cl-1 (aq) NaCl (s)

a.Increase
b.Decrease
c.Remain the same
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1. In which direction will the point of equilibrium shift when a catalyst is added to the following equilibrium system?

KNO3 + 34.7 kJ ---> K+ (aq) + NO3- (aq)

c.No shift

Catalyst won't affect equilibrium and the rates, as it only speeds up the reaction by decreasing the activiation energy.

2.The magnitude of Keq depends on

c.Temperature

Fact.

3.In which direction will the point of equilibrium shift when the pressure is decreased in the following equilibrium?

H2 (g) + Cl2 (g) ---> 2 HCl (g)

c.No shift

When pressure is decreased, equilibrium shifts to the greatest number of moles; there are equal number of moles on both sides.


4.The equilibrium constant can change significantly with a change in

c.Temperature

Only temperature effects rate constant.


5.In the following equilibrium, when sodium ion is removed, the concentration of chloride ion will
Na+ (aq) + Cl- (aq)---> NaCl (s)

a.Increase

If Na+ is taken out, equilibrium will shift to the left to increase [Cl-].

A 15mg strip of Magnesium metal reacts in 5.0 mL of 1.0M HCl over a given period. Evaluate the (mol HCl)/(mol Mg) ratio for the reaction. moles of each Mg and HCl by using their masses?

First convert mass to grams: 15 mg = 0.015 g

n(Mg) = 0.015 g / 24.31 g-mol = 0.00062 mol

For HCl, determine from product of volume (in liters) and molarity:

n(HCl) = (0.005 L)(1.0 M) = 0.0050 mol

So the ratio (mol HCl/mol Mg) = 0.0050 / 0.00062 = 250 / 31

If 2 moles of an ideal gas at STP are subjected to a new pressure of 24.7 kPa, what will be the volume of the gas? Answer in units of L.

PV=nRT... Solve for V
V=nRT/P
V=2 mol x 8.314 LkPa/molK x 273K / 24.7kPa
V=184 L

You are studying flower color in tulips. Yellow is dominant over white. You have discovered a yellow flower but are unsure of its precise genotype. What are the possible genotype(s) for this flower?

Yy or YY

A mother is a carrier for color blindness and a father is affected by color blindness.Is this trait dominant?

No. This trait cannot be dominant because the mother is a carrier which means she is a heterozygous. If this trait is dominant, then she will be affected too.

An organism's interrelationships within its environment constitute its?

A) trophic level
B) dominance rank
C) ecological niche
D) caste
E) habitat

ANSWER
C. Every organisms in an ecosystem plays their respective role (niche) to maintain a balanced environment.

Biology 3 Questions

1. What determines the size of a grape or a kernel of corn?
a. a combination of genetics and environmental factors
b. genetics alone
c. environmental factors alone

2. Because the grapes or corn come from a single genetic source, you would expect _________________.
a. that all the grapes or corn would fall into a fairly narrow range of values
b. that the grapes or corn would exhibit a great deal of variation
c. that all the grapes or corn would measure exactly the same

3. Which of the following is considered a measure of central tendency (indicates what the central value is, rather than the deviation from the center)?
a. average
b. range
c. variation


ANSWERS
1: A
2: A
3: A

Which of the following are empirical formulas?(Could be as many as 3) 1. H2O2 2. H2SO4 3. S2Cl2 4. CH2O 5. N2 6. C2H4

Which of the following are empirical formulas?(Could be as many as 3)
1. H2O2 
2. H2SO4 
3. S2Cl2 
4. CH2O 
5. N2 
6. C2H4

H2O2 = 2(HO) = HO

H2SO4

S2Cl2 = 2(SCl) = SCl

CH2O

N2 = 2N = N

C2H4 = 2(CH2) = CH2

In a sealed container, there is a 1.6 mol sample of ideal gas. the temperature of the room is 22 C and the volume of the container is 1 L. How much pressure is built up in this container?

Ideal Gas Law is PV = nRt where R = .0821

P * 1L = 1.6mol *.0821 * (273+22)

P = 38.75 atm