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June 2011 Chemistry Regents #31-40
Highlight to reveal answers and explanations
Questions | Answer | Link | Explanations | ||||
| 31 Compared to the atoms of a nonmetal in Period 3, the atoms of metals in Period 3 have (1) fewer valence electrons (2) more valence electrons (3) fewer electron shells (4) more electron shells | 1 | Link | metals are on the left of a period and have fewer valence electrons (last number in the configuration) | ||||
| 32 Which elements are malleable and good conductors of electricity? (1) iodine and silver (2) iodine and xenon (3) tin and silver (4) tin and xenon | 3 | Link | malleable (hammered into sheets) and conductors are properties of metals left of the staircase are the metals | ||||
| 33 Which atom in the ground state requires the least amount of energy to remove its valence electron? (1) lithium atom (2) potassium atom (3) rubidium atom (4) sodium atom | 3 | Link | least amount of energy to remove an electron LOWEST Ionization energy (Table S) | ||||
| 34 What is the chemical formula of iron(III) sulfide? (1) FeS (2) Fe2S3 (3) FeSO3 (4) Fe2(SO3)3 | 2 | Link | Iron(III) Sulfide Fe3+ S2- ==> Fe2S3 | ||||
| 35 What is the percent composition by mass of sulfur in the compound MgSO4 (gram-formula mass =120. grams per mole)? (1) 20.% (2) 27% (3) 46% (4) 53% | 2 | Link | (32/120) x 100%=27% | ||||
| 36 Which compound becomes less soluble in water as the temperature of the solution is increased? (1) HCl (2) KCl (3) NaCl (4) NH4Cl | 1 | Link | Table G | ||||
| 37 Given the balanced equation representing a reaction: 2H2 + O2 ==> 2H2O What is the mass of H2O produced when 10.0 grams of H2 react completely with 80.0 grams of O2? (1) 70.0 g (2) 90.0 g (3) 180. g (4) 800. g | 2 | Link | Find the missing mass 10g + 80g==> X X=90g | ||||
38 Given the two formulas representing the same compound:
Which statement describes these formulas? (1) Formulas A and B are both empirical. (2) Formulas A nd B are both molecular. (3) Formula A is empirical and Formula B is molecular. (4) Formula A is molecular and Formula B is empirical. | 3 | Link | they come from the same compound A is a reduced formula so it is empirical B is a multiple of A so it molecular | ||||
| 39 Given the balanced equation representing a reaction: Zn(s) +H2SO2(aq) ==> ZnSO4(aq) + H2(g) What type of reaction is represented by this equation? (1) decomposition (3) single replacement (2) double replacement (4) synthesis | 3 | Link | single replacement A+ BC==> AC + B only one element replaces another | ||||
| 40 In a laboratory where the air is 22oC, a steel cylinder at 100.oC is submerged in water at 40.oC. In this system, heat flow from (1) both the air and the water to the cylinder (2) both the cylinder and the air to the water (3) the air to the water and from the water to the cylinder (4) the cylinder to the water and from the water to the air | 4 | Link | order of temperature (heat flows from hot to cold) 100oC steel cylinder in water at 40oC (no contact with the air) water at 40oC to the air at 22oC |