January 2011 Chemistry Regents #11-20

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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

Questions 51-53 Questions 54-55 Questions 56-57 Questions 58-59 Questions 60-61 Questions 62-63 Questions 64-65 Questions 66-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-80 Questions 81-83

 

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Questions

AnswerExplanations
11 What is the total number of electron pairs shared between the two atoms in an O2 molecule?
(1) 1   (3) 6
(2) 2   (4) 4
2oxygen has a double bond so 2pairs of electrons
12 When an atom of lithium loses an electron, the atom becomes a
(1) negative ion with a radius smaller than the radius of the atom
(2) negative ion with a radius larger than the radius of the atom
(3) positive ion with a radius smaller than the radius of the atom
(4) positive ion with a radius larger than the radius of the atom
3losing electrons makes it positive and smaller
13 Given the balanced equation representing a reaction:
2NaCl → 2Na + Cl2
To break the bonds in NaCl, the reactant must
(1) absorb energy    (3) destroy energy
(2) create energy     (4) release energy
1breaking bonds requires energy
14 A molecular compound is formed when a chemical reaction occurs between atoms of
(1) chlorine and sodium
(2) chlorine and yttrium
(3) oxygen and hydrogen
(4) oxygen and magnesium
3molecular is covalent

two nonmetals

15 Which substance can not be broken down by chemical means?
(1) ammonia   (3) methane
(2) antimony   (4) water
2definition of an element
16 Which two physical properties allow a mixture to be separated by chromatography?
(1) hardness and boiling point
(2) density and specific heat capacity
(3) malleability and thermal conductivity
(4) solubility and molecular polarity
4chromatography= solubility and polarity
17 The solubility of KCl(s) in water depends on the
(1) pressure on the solution
(2) rate of stirring
(3) size of the KCl sample
(4) temperature of the water
4solubility of a solid depends temperature
18 Which sample of water contains particles having the highest average kinetic energy?
(1) 25 mL of water at 95°C
(2) 45 mL of water at 75°C
(3) 75 mL of water at 75°C
(4) 95 mL of water at 25°C
1highest average kinetic energy=highest temperature
19 Under which conditions of temperature and pressure does carbon dioxide gas behave most like an ideal gas?
(1) low temperature and low pressure
(2) low temperature and high pressure
(3) high temperature and low pressure
(4) high temperature and high pressure
3ideal gas is like an ideal vacation

high temperature and low pressure

20 Which process results in a chemical change?
(1) tearing tin foil
(2) melting an iron bar
(3) crushing an aluminum can
(4) burning magnesium ribbon
4chemical changes are reactions

Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

Questions 51-53 Questions 54-55 Questions 56-57 Questions 58-59 Questions 60-61 Questions 62-63 Questions 64-65 Questions 66-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-80 Questions 81-83

 
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