CHEM134 C001 PRACTICE EXAM QUESTIONS WITH CORRECT DETAILED ANSWERS | ALREADY GRADED A+RECENT VERSION

CHEM134 C001 PRACTICE EXAM QUESTIONS WITH CORRECT DETAILED ANSWERS | ALREADY GRADED A+RECENT VERSION 1) Ammonium chloride - answer nh₄cl 2) Magnesium chloride - answer mgcl₂ 3) Iron(iii) chlorate - answer fe(clo₃)₃ 4) Carbon dioxide - answer co₂ 5) Dihydrogen monoxide - answer h₂o 6) Dinitrogen tetroxide - answer n₂o₄ 7) Dinitrogen trioxide - answer n₂o₃ 8) Nitrogen trioxide - answer no₃ 9) Sodium chloride - answer nacl 10) How many protons and electrons are in a mg^2+cation? - answer 12p, 10e 11) Sodium ______ one electron to become a +1 cation. - answer loses. Let's go ahead and see why this makes sense. Sodium is element #11. A neutral sodium atom has 11 protons and 11 electrons. If the number of protons changes, then it wouldn't be sodium any longer. By losing one electron, the overall charge becomes (+11) + (−10) = +1. Na→ na^++ e− 12) How many protons and electrons are in an o2−anion? - answer 8p, 10e 13) How many protons and electrons are in an n 3−anion? - answer 7p, 10e 14) The following ions represent an isoelectronic series: all have the same number of electrons. Rank the ions in order of decreasing electronic charge. - answer fluorine with 10e Oxygen with 10e Nitrogen with 10e 15) Match each property about atoms with the phrase describing the fundamental source. Element identity - answer protons 16) Match each property about atoms with the phrase describing the fundamental source. Ions - answer electrons 17) Place the number of neutrons next to the correct isotope. 13c - answer 7n 18) Place the number of neutrons next to the correct isotope. 12c - answer 6n 19) Place the number of neutrons next to the correct isotope. 14c - answer 8n 20) Rank the following isotopes in order of increasing number of neutrons. - answer 2h 81br 238u 21) Label each property of silicon as metallic or nonmetallic. Lustrous - answer metallic 22) Bromine has two naturally occurring isotopes, 79br and 81br. 79br has an exact mass of 78.9183371 amu and is 50.69% abundant. Calculate the exact isotope mass of 81br. Do not enter the units of amu. - answer 80.91 23) Label each property of silicon as metallic or nonmetallic. Brittle - answer nonmetallic 24) Label each property of silicon as metallic or nonmetallic. Good conductor - answer metallic 25) Label each property of silicon as metallic or nonmetallic. High melting point - answer metallic 26) What is the chemical symbol of the element located in the 2nd period that naturally occurs as a diatomic gas? - answer f 27) The amino acids in the active site can be involved in all of these processes, except: A. Binding of the substrate. B. Becoming part of the product of the reaction. C. The actual chemical mechanism for the reaction. d. Binding of some necessary cofactor for the reaction. E. All of these can be functions of the amino acids in the active site - answer b. Becoming part of the product of the reaction. 28) The critical serine residue in the active site of chymotrypsin functions as A. A nucleophile. B. An electrophile. C. A base. D. A methyl donor. - answer a. A nucleophile. 29) The active site of chymotrypsin contains all of the following, except: A. Histidine residue. B. A magnesium ion. C. Hydrophobic pocket to bind the substrate. D. Serine residue. E. All of these are in the active site of chymotrypsin. - answer b. A magnesium ion. 30) The ph profile of an enzyme can help identify specific amino acids in the active site because: A. All enzymes have a ph optimum B. Only the active site amino acids can detect changes in ph c. Acidic and basic amino acids are often involved in the active site and ph changes can change their ability to catalyze a reaction D. The ph optimum is always the pi of the most critical amino acid in the active site - answer c. Acidic and basic amino acids are often involved in the active site and ph changes can change their ability to catalyze a reaction 31) Which groups of amino acids are likely to be found in the active site of an enzyme? A. Leucine, lysine, alanine. B. Cysteine, isoleucine, phenylalanine. C. Tyrosine, threonine, leucine. D. Serine, histidine, aspartate. - answer d. Serine, histidine, aspartate. 32) Labeling the amino acid residues in the active site of an enzyme requires a. A reagent structurally similar to the substrate. B. A highly polar reagent. C. A reagent that contains an aromatic group. D. A reagent that contains a halogen atom. - answer a. A reagent structurally similar to the substrate. 33) Which of the following is unlikely to occur in binding of a substrate to an enzyme? A. Stereospecific interactions. B. Hydrogen bonding. C. Adsorption to surfaces of metallic catalysts. D. Interactions with metal-ions. - answer c. Adsorption to surfaces of metallic catalysts. 34) Which of the following amino acid side chains would best serve as a general acid, assuming the protein functions at a ph of 7? A. Alanine b. Aspartic acid C. Lysine d. Asparagine - answer c. Lysine 35) Metal ions play an important role in reaction mechanisms because A. They block the active site of enzymes so that inhibitors cannot bind. B. They can act as lewis acids. C. Water is excluded from the active site when metal ions are bound. D. They prevent protein aggregation. - answer b. They can act as lewis acids. 36) The serine in the active site of chymotrypsin functions as A. A lewis acid. B. A metal ion. C. An electrophile. D. A nucleophile. - answer d. A nucleophile. 37) Important mechanisms of enzymatic catalysis include A. Nucleophilic reactions B. General acid-base catalysis C. Lewis acid-base catalysis D. All of these - answer d. All of these 38) Enzymes that catalyze similar functions will invariably have A. Similar overall structures. B. Serine in their active sites. C. Histidine in their active sites. d. Active sites that can catalyze the reactions in question. - answer d. Active sites that can catalyze the reactions in question. 39) A transition-state analog is likely to bind to an enzyme A. More tightly than the substrate. B. Less tightly than the substrate. C. About as tightly as the substrate. D. At a site other than the catalytic site. - answer a. More tightly than the substrate. 40) Abzymes A. Invariably bind to pyridoxal phosphate. B. Are antibodies with catalytic activity. C. Differ markedly from transition states in enzymatic reactions. D. Have proline as part of their structure. - answer b. Are antibodies with catalytic activity. 41) How are cofactors bound to their enzymes? A. Always covalently B. Always non-covalently C. Either covalently or non-covalently - answer c. Either covalently or non-covalently 42) Which of the following is not true about b vitamins? A. They are usually fully active in the form we eat them B. They are usually water soluble C. Niacin and riboflavin are examples D. They are important in many metabolic reactions - answer a. They are usually fully active in the form we eat them 43) Cofactors are A. Non-protein in chemical nature. B. Always small proteins. c. Modified amino acids. D. Never required for enzymatic activity. - answer a. Non-protein in chemical nature.