Chemical Processes Flashcards
Which molecule is nonpolar? A. carbon monoxide B. acetone C. carbon tetrachloride D. ethanol
C. Carbon tetrachloride is the only nonpolar compound because it is the only compound listed in which all of the electrons are shared equally across the four same bonds; each chlorine atom bonds with the carbon atom with the same force. Consequently, carbon tetrachloride exhibits a tetrahedral structure with geometric symmetry
A 50ml solution of HCl is diluted to 250ml at 10M. What was the initial concentration of the HCl? A. 500M B. 50M C. 5M D. 0.5M
B. The product of the initial concentration and the initial volume is equal to the product of the final concentration and the final volume of the solution. This can be remembered as c1v1=c2v2
Substitute the known quantities and solved for the unknown: c1:c150ml=10M250ml —-> c1=50M
What product results from treating ethanol with pyridinium chlorochromate (PCC)? A. acetaldehyde B. formaldehyde C. acetone D. acetic acid
A. PCC is a mild oxidizing reagent used to oxidize primary alcohols to aldehydes. Ethanol, a primary alcohol, treated with PCC results in a 2 carbon aldehyde called ethanal or acetaldehyde
What are the relative pKa values of the following compounds? I. H2O, II. NH3, III. HCl, IV. CH3COOH A. II > I > IV > III B. IV > II > III > I C. III > IV > I > II D. I > III > IV > II
A. Categorize the options as strong acids, weak acids, neutral, weak bases, or strong bases and rank. Low pKa values correspond to higher acidity levels Carboxylic acids= 4-5 pKa Water= 15.7 pKa Amines= 36 pKa Alcohols= 15-18 pKa
What is the oxidation number of nitrogen in NF3? A. -3 B. 0 C. +2 D. +3
D. The sum of the oxidation numbers of a neutral compound is always 0. The oxidation number of fluorine is always -1. Let x represent the oxidation number of N, set up the equation, and solve for x: x + (-1) *3=0 —> x=3
What is the conjugate base of sulfuric acid? A. H2SO3 B. HSO4- C. SO4 -2 D. H3SO4+
B. In a solution, sulfuric acid will donate an H+ to water to form hydronium H3O+. The loss of the single H+ results in H2SO4 becoming HSO4-
What would be the result of increasing the number of nucleophiles in a Sn1 reaction?
A. it would increase the rate exponentially
B. it would increase the rate linearly
C. it would decrease the rate
D. it would have no effect
D. Sn1 reaction are substitution reactions that depend on reagents attracted to electrons (electrophiles). Sn1 reactions do not depend on the number of nucleophiles involved in the reaction. Consequently, altering the concentration of nucleophiles does not alter the rate of reaction
Which of the following species cannot hydrogen bond with itself? A. ethanol B. acetic acid C. ammonia D. acetone
D. Hydrogen bonds occur between hydrogen of one molecule with an electronegative atom (oxygen, nitrogen, or fluorine) of another atom. Consequently, acetone is unable to hydrogen bond with itself. The hydrogen atoms in acetone are covalently bonded to carbon atoms and not a strong electronegative atom like nitrogen, oxygen, or fluorine
Which effect would result from increasing the molar mass of a gas? A. an increase in temperature B. an increase on pressure C. an increase in volume D. a decrease in the rate
D. Graham’s Law of Diffusion states that the rate of diffusion is inversely proportional to the molecular weight of the molecule. Let the initial molar mass be 5, and the increased molar mass be 10, substitute these values into Graham’s equation and compare the results
Rank the following amino acids by increasing pl (isoelectric point): I. Lys, II. Leu, III. Asp A. I < II < III B. III < II < I C. II < I < III D. III < I < II
B. The pl of a molecule is its isoelectric point, or the point at which, in this case, the amino acid will have no overall charge. Categorizing the amino acids: I is positively charge and basic; II is nonpolar and neutral; III is polar and acidic. Acidic amino acids on average have the lowest pl, nonpolar amino acids have a higher pl, and basic amino acids carry the largest pl
What is the result of adding HBr and hydrogen peroxide to propene? A. 2-propanol B. 1-propanol C. 2-bromopropane D. 1-bromopropane
D. In the presence of an organic peroxide, the addition of HBr and peroxide to a propene results in an anti-Markovnikov product in which the hydrogen becomes attached to the carbon with fewer hydrogens connected to it. The product of the addition is CH3CH2CH2Br or 1-bromopropane
Which of the following has the highest boiling point? A. methanol B. n-propanol C. isopropanol D. ethanol
B. Boiling points primarily depend upon the cohesive forces between molecules. When dealing with molecules of relatively similar molecular weights, the boiling points will depend upon the functional groups involved, and as the molecular weight of the molecule increases, the boiling point also increases. Lastly, branching decreases boiling point. With these considerations, n-propanol will exhibit the highest boiling point of the options
The rate law for a reaction is of the second order. Which statement is true?
A. the rate must depend on both reactants
B. the reaction must depend on the square of one reactant
C. the reaction must depend on only k squared
D. the reaction must depend on at least one of the reactants
D. In a second-order reaction the reaction rate is dependent upon either the product of the reactants, or the square of one of the reactants
The solubility of KCl in seawater would be ____ than the solubility of KCl in tap water.
A. higher
B. the same as
C. lower
D. KCl would completely insoluble in sea water as K cannot dissociate in water
C. Potassium chloride is a metal halide salt. While it dissolves readily in water, its solubility is lowered because of the common ions present in the seawater. This is otherwise known as the common ion effect
An electron pair donor is best classifies as a: A. strong acid B. Bronsted-Lowry acid C. Lewis acid D. Lewis base
D. By definition, a Lewis base is an electron pair donor. A Lewis acid, on the other hand, is an electron pair acceptor
Which reaction can be spontaneous under favorable conditions? I. -TH, +TS II. -TH, -TS III. +TH, -TS A. I only B. II only C. I and III only D. I and II only
D. Under favorable conditions, TH < 0, and TS > 0, a reaction will be spontaneous at any temperature. If one of the conditions is unfavorable with either TH > 0 or TS <0, a reaction can be spontaneous if it satisfies TG < 0 using the standard-state free energy of reaction equation: TG=TH-TTS. Roman numeral III can never be spontaneous
Which of the following alcohols is the most easily dehydrated? A. (CH3)3C-OH B. (CH3)2CH-OH C. CH3CH2-OH D. CH3-OH
A. Classify the alcohols as primary, secondary, or tertiary: A is tertiary because the -OH group is directly attached to the 3 alkyl groups; B is secondary because the carbon attached to the -OH is connected to two carbon atoms; C is primary because the carbon connected to the -OH group is connected to one carbon atom; and although D lacks an attached alkyl group, it is considered primary.. As tertiary alcohols form the most stable carbocations, A is correct
If the pl of a specific protein is 6, what is the charge on the protein when it is in a solution of pH 9? A. - B. 0 C. + D. cannot be determined
A. The pl, or the isoelectric point, is the pH at which a molecule exhibits a net charge of 0. When the pl of a molecule is less than the pH of the surrounding solution, the molecule is deprotonated and its charge is negative. The 3 situations:
pH < pl = protonated +
pH > pl = deprotonated -
pH = pl = neutral charge
What is the hybridization of the carbons in benzene? A. s B. sp C. sp2 D. sp3
C. Benzene, C6H6, is a plana regular hexagon made up of a ring of carbon atoms. Each carbon is bonded with 2 other carbon atoms as well as a hydrogen atom fro a total of 3 bonded atoms. Consequently, the hybridization of benzene is sp2
