August 2006 Chemistry Regents #41-50
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41 An unsaturated aqueous solution of NH3 is at
90.°C in 100. grams of water. According to
Reference Table G, how many grams of NH3
could this unsaturated solution contain?
(1) 5 g (3) 15 g
(2) 10. g (4) 20. g
|1||NH3 would be saturated with 10 grams. Unsaturated is less than 10g.|
|42 How many total moles of KNO3 must be dissolved
in water to make 1.5 liters of a 2.0 M solution?
(1) 0.50 mol (3) 3.0 mol
(2) 2.0 mol (4) 1.3 mol
|3||M=mol/L; mol= M/L=2.0/1.5|
|43 Which statement explains why low temperature
and high pressure are required to liquefy
(1) Chlorine molecules have weak covalent bonds.
(2) Chlorine molecules have strong covalent bonds.
(3) Chlorine molecules have weak intermolecular forces of attraction.
(4) Chlorine molecules have strong intermolecular forces of attraction.
|3||Cl2 is nonpolar and have
weak intermolecular forces
van der waals
|44 Given the balanced equation representing a
CH4(g) + 2O2(g) --> 2H2O(g) + CO2(g) + heat
Which statement is true about energy in this reaction?
(1) The reaction is exothermic because it releases heat.
(2) The reaction is exothermic because it absorbs heat.
(3) The reaction is endothermic because it releases heat.
(4) The reaction is endothermic because it absorbs heat.
|1||heat is on the right of the arrow, it is exothermic and releases heat|
|45 Given the reaction at equilibrium:
N2(g) + 3H2(g) -->2NH3(g) + 91.8 kJ
What occurs when the concentration of H2(g) is increased?
(1) The rate of the forward reaction increases and the concentration of N2(g) decreases.
(2) The rate of the forward reaction decreases and the concentration of N2(g) increases.
(3) The rate of the forward reaction and the concentration of N2(g) both increase.
(4) The rate of the forward reaction and the concentration of N2(g) both decrease.
|1||LeChaterliers Principle, add a reactant it shifts right, reactants decrease [H2] and products increase.|
|4||Potential Energy Diagrams
Difference in products and reactants is Delta H
|47 Based on bond type, which compound has the
highest melting point?
(1) CH3OH (3) CaCl2
(2) C6H14 (4) CCl4
|3||The Ionic One (Metal and
the other 3 are covalent (made of all nonmetals)
|1||(Mass x %) x (mass x %) / 100%
they distributed the divide by 100
|49 Which list of the phases of H2O is arranged in
order of increasing entropy?
(1) ice, steam, and liquid water
(2) ice, liquid water, and steam
(3) steam, liquid water, and ice
(4) steam, ice, and liquid water
|2||Entropy is Randomness, increase from
Solid to liquid to gas
|50 Solution A has a pH of 3 and solution Z has
a pH of 6. How many times greater is the
hydronium ion concentration in solution A than
the hydronium ion concentration in solution Z?
(1) 100 (3) 3
(2) 2 (4) 1000
|4||for each pH value it is 10x's more
3 pH units 1000 xs
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