August 2010 Chemistry Regents #31-40
Highlight to reveal answers and explanations
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Questions |
Answer | Explanations |
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2 | Isotopes- same number of protons different number of neutrons |
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2 | there are more neutrons in O-17 neutrons 9 protons 8 |
| 33 The bond between which two atoms is most polar? (1) Br and Cl (3) I and Cl (2) Br and F (4) I and F |
4 | find the largest electronegativity
difference Table S bonds=bend= Bonds compare ElectroNegativity Differences |
| 34 In the formula X2(SO4)3, the X represents a metal. This
metal could be located on the Periodic Table in (1) Group 1 (3) Group 13 (2) Group 2 (4) Group 14 |
3 | SO4 has a charge of 2-
and there are 3 of them=-6 X must have a charge of +3 (you only have 2 of them) Group 13 |
| 35 At STP, which element is solid, brittle, and a poor
conductor of electricity? (1) Al (3) Ne (2) K (4) S |
4 | the nonmetal, not Ne it is a gas |
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2 | conservation of mass what goes in must come out. Subtract. |
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1 | count the atoms=molecular reduce to lowest whole number ratio=empirical |
| 38 Which element forms an ionic compound when it reacts
with lithium? (1) K (3) Kr (2) Fe (4) Br |
4 | the nonmetal, not Kr it doesn't react |
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2 | SNAP=symmetrical is nonpolar, asymmetrical is polar |
| 40 Which compound has both ionic and covalent bonds? (1) CO2 (3) NaI (2) CH3OH (4) Na2CO3 |
4 | need a metal for it to be ionic and 2 nonmetals for it to be covalent |