June 2012 Chemistry Regents #41-50
Highlight to reveal answers and explanations
Questions | Answer | Links | Explanations |
41 At 50.oC and standard pressure, intermolecular forces of attraction are strongest in a sample of (1) ethanoic acid (2) ethanol (3) propanone (4) water | 1 | link | Table H, the lowest vapor pressure has the strongest IMFs |
42 At 101.3 kPa and 298 K. what is the total amount of heat released when one mole of aluminum oxide, Al2O3(s), is formed from its elements? (1) 393.5 kJ (2) 837.8 kJ (3) 1676 kJ (4) 3351 kJ | 3 | link | use table H, find Al2O3 delta H =-3351kJ this reaction is for 2 moles, you need 1 mole, so half the amount of energy |
43 Given the balanced equation representing a reaction: What occurred as a result of this reaction?(1) Energy was absorbed, and entropy increased.(2) Energy was absorbed, and entropy, decreased(3) Energy was released, and entropy increased(4) Energy was released, and entropy decreased. | 1 | link | since energy is a reactants (left side of arrow) it is absorbed
entropy is randomness, which increases... liquid to gases |
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44.Given the potential energy diagram representing a reversible reaction;
The activation energy for the reverse reaction is represented by(1) A + B (2) B + C (3) B + D (4) C + D | 2 | link | go up the hill backwards B+C |
2 | link | chlorine goes on the 2nd carbon in of a 4 carbon chain it can start from the right | |
46 'Which formula represents an unsaturated hydrocarbon? (1) CH4 (2) C2H4 (3) C3H8 (4) C4H10 | 2 | link | use the general formulas on Table Q unsaturated is not an alkane not CnH2n+2 |
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47 Which ion is most easily reduced? (l ) Zn2+ (2) Mg2+ (3) Co2+ (4) Ca2+ | 3 | link | Table J, reduction is towards the bottom Oxidation is on top |
48 Given the balanced equation representing a reaction: According to one acid-base theory, the H2O(l) molecules act as (1) a base because they accept H + ions(2) a base because they donate H+ ions (3) an acid because they accept H + ions(4) an acid because they donate 1-1+ ions | 1 | link | H2O takes an H+ and becomes H3O+ it acts as a base |
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49 Which equation represents an oxidation reduction reaction? | 3 | link | look for oxidation number changing or find the free element |
2 | link | natural 1 reactant artificial 2 reactants |