ALL KNEWTON TESTS
Consider the reaction shown below. Before the reaction occurs, the concentrations of A and B are each 0.0280 M. If the concentration of B at equilibrium is 0.0112 M, what is the equilibrium constant? A(g)+B(g)⇌2C(g)
9.00
In a prospective buffer system, as the strength of the weak acid decreases (i.e., as the pKa increases), what happens to the strength of the conjugate base?
???? DEF NOT 'A weak acid has a weak conjugate base.'
Consider the reaction below. According to the Bronsted-Lowry definition, what acts as the conjugate acid when the reaction proceeds in the forward direction? CN−+H2O⇌OH−+HCN
???? DEF NOT H20
Calculate the pH of a solution made with 0.01 M CHES (N-cyclohexyl-2-aminoethanesulfonic acid) and 0.06 M hydrochloric acid. The pKa of CHES is 9.5. Your answer should have two significant figures.
????? DEF NOT 8.8
Lead-212 decays into bismuth-212 by emitting which particle?
A beta particle
Which of the following correctly describes how a scintillation counter works?
A material called a scintillator emits light on exposure to ionizing radiation, and the light is further converted to an electrical signal by an optical sensor.
Which substance has a pH that is higher than pure water?
AMMONIA
2H2S can react to yield 2H2 and S2. Which of the following changes will shift the equilibrium to reactants? (select all that apply)
Add more H2. Add more S2.
Which of the following is a characteristic of aldehydes?
Aldehydes contain an oxygen atom. The carbonyl group in an aldehyde must be attached to a hydrogen atom.
Which of the following best indicates the meaning of the term autoionization?
Autoionization is a reaction between two molecules of the same neutral substance to produce an ion pair.
Which of the following is the correct molecular formula for 2,3-dimethyl-1-pentanol?
C7H16O
What is the the most widely used ether?
Diethyl ether
What is the formula for sulfuric acid?
H2SO4
Complete the chemical equation for the acid ionization of hydrochloric acid HCl in water.
H30+ / Cl-
Which of the following best describes the term homogeneous equilibrium?
Homogeneous equilibrium is the equilibrium in a system in which all reactants and products are present in a single phase
What element could be used as fuel in a nuclear fusion reactor?
Hydrogen
Potassium hydroxide (KOH) and nitric acid (HNO3) react in an aqueous solution. What are the products of the reaction?
KNO3 and H2O
What is the equilibrium expression for the reversible reaction shown below? 4NH3(g)+7O2(g)⇌4NO2(g)+6H2O(g)
Kc=[NO2]4[H2O]6/[NH3]4[O2]7
Which of the following is directly controlled in a nuclear power plant?
NOT CORRECT!!!!! The number of neutrons produced by each nucleus undergoing fission in the nuclear fuel NOT CORRECT!!!!!
Supercritical mass is:
NOT CORRECT!!!!!! the amount of fissionable material that cannot sustain a chain reaction. NOT CORRECT!!!!!!
Convert an absorbed dose of 5.05rad of neutron radiation into Sv units. Use an RBE of 2.00 for neutron radiation.
NOT CORRECT!!!!!!!! 101.1Sv NOT CORRECT!!!!!!!!
Why is a carbonyl group polar?
Oxygen is significantly more electronegative than carbon.
Which of the following statements comparing beta decay and positron emission are NOT true?
Particles released during both types of decay processes are deflected the same way in an electric field
2-heptanone is less dense than water and only slightly soluble in water, so as a result, 2-heptanone floats on water. Which among the following statements is true as it relates to its insolubility?
Since 2-heptanone has more than 5 carbons, it is insoluble in water. The effect of the nonpolar alkyl groups dominates over the effects of the carbonyl group.
Which of the following conditions are necessary for a change in total pressure to result in a change to the relative amounts of reactants and products for a gas phase reaction that is at equilibrium?
The pressure change is a result of changing the volume of the container. The number of moles of gas on each side of the reaction are different.
Identify the option below that exemplifies how the intrinsic chemical properties of a reactant affect the rate of reaction.
When exposed to air, sodium reacts completely overnight, whereas iron barely reacts.
ethanol can be synthesized from ethylene and water, using:
acid catalysis
Radioactive tracers are used in _______________. Select the correct answer below: medical applications analyzing the geological formation around oil wells tracking engine wear all of the above
all of the above
Radiometric dating has been responsible for breakthrough discoveries in: Select the correct answer below: geology biology anthropology all of the above
all of the above
Which of the following alcohols is a liquid at room temperature? ethanol butanol methanol all of the above
all of the above
Which of the following is included in a nuclide symbol?
all of the above
Which of the following is best described as a proton acceptor?
bronsted-Lowry base
When propanone is reduced, the double bond between the carbon and oxygen becomes a single bond and hydrogen atoms are added to:
carbon and oxygen
Identify the product(s) that form when an aldehyde undergoes incomplete combustion.
carbon monoxide
The rate of a reaction is:
directly proportional the to rate of collisions
If a catalyst is added to a reaction, the reaction will most often generate products:
more rapidly
A patient has symptoms including increased breathing rate, numbness, muscle spasms, and nausea. The blood pH is checked and found to be 7.5 and CO2 pressure is 37 torr. The patient most likely has what condition?
respiratory alkalosis
In a chemical equation, the symbol between the reactants and the products that is used to indicate an equilibrium reaction is _____________.
two stacked arrows: one pointing to the left and one to the right. reactants⇌products
Determine the pKb for the base B given that the equilibrium concentrations are [B]=2.64 M, [HB+]=1.5 M, and [OH−]=1.2 M. Report your answer with two decimal places.
0.17
Which of the following helps us to predict the effect of change in temperature on a reaction system?
Le Châtelier's principle
Le Châtelier's principle is best described by which of the following descriptions?
Le Châtelier's principle states that when a chemical system at equilibrium is disturbed, the system will return to equilibrium by counteracting the disturbance.
What types of intermolecular forces can be found in ketones?
London dispersion forces dipole-dipole interactions
Which of the following solutions has a greater concentration of hydroxide ions? Solution A has a pOH of 6.1. Solution B has a pOH of 12.5.
Solution A
The melting point of phenol is 40.5∘C and that of toluene is −95∘C. What is the best explanation for this difference?
The (−OH) group on phenol can form hydrogen bonds, and the −CH3 group on toluene cannot.
What affects the solubility of C5H11OH in water?
the hydroxyl group and the alkyl groups
What will be the product formed by the oxidation of 4-hydroxy phenol?
0 II II 0
The half-life of a radioisotope is 50.0 seconds. What is the rate constant k for the radioactive decay of this isotope?
0.0139 s
What is the hydroxide concentration in a solution at 25.0∘C with [H3O+]=5.9×10−13 M? Report your answer with two significant figures.
0.017M
The initial concentrations of PCl3 and Cl2 in the reaction below are each 0.0371 M. If the initial concentration of PCl5 is 0 M and the equilibrium constant is Kc=0.021, what will be the concentration of PCl3 when the system reaches equilibrium? PCl5(g)↽−−⇀PCl3(g)+Cl2(g)
0.019 M
2A+B↽−−⇀C If equilibrium concentrations are[B]=1.4 Mand[C]=0.85 M, andKc=2.5, what is the equilibrium concentration ofA? Your answer should have two significant figures.
0.49
he end point in a titration of a 45ml sample of aqueous HCl was reached by addition of 30ml of 0.6M titrant. The titration reaction is 2HCl+Ca(OH)2→CaCl2+2H2O What is the molar concentration ofHCl? Give your answer in one significant figure.
0.8
What is the equilibrium constant for the reversible reaction in aqueous medium below given that the respective concentrations of A, B, C, and D are 0.0117 M, 0.00440 M, 0.00550 M, and 0.00780 M? 3A+3B⇌2C+3D Report your answer with three significant figures.
105
A sample of technetium-99 was used in a procedure to image the heart muscle of a patient 18 hours ago and now 2.50 mCi remain. What was the size of the original sample? (Technetium-99 has a half life of 6 hours.)
20.0 mCi
Name a secondary alcohol with the formula C5H11OH.
3-pentanol
What is the pH of a solution with [H3O+]=2.6×10−5 M? Report your answer to the hundredths place.
4.59
The initial concentration of acid HA in solution is 0.39 M. If the pH of the solution at equilibrium is 0.76, what is the percent ionization of the acid? Remember to use correct significant figures in your answer (round your answer to the nearest whole number). Do not include the percent symbol in your response.
45%
A 10∘C solution has a pH of 8.0. At this temperature, Kw=2.93×10−15. What is the pOH of the solution?
6.5
As text, an aldehyde group is represented as:
-CHO