August 2009 Chemistry Regents #11-20
Highlight to reveal answers and explanations
Questions | Answer | Explanations |
| 11 Which formula represents a molecular compound? (1) HI (3) KCl (2) KI (4) LiCl | 1 | Molecular is covalent= nonmetal to nonmetal |
| 12 Which element has the greatest density at STP? (1) scandium (3) silicon (2) selenium (4) sodium | 2 | use Table S |
| 13 Particles are arranged in a crystal structure in a sample of (1) H2(g) (3) Ar(g) (2) Br2(l) (4) Ag(s) | 4 | SOLID |
| 14 The relatively high boiling point of water is due to water having (1) hydrogen bonding (2) metallic bonding (3) nonpolar covalent bonding (4) strong ionic bonding | 1 | FON with H has hydrogen bonding between molecules |
| 15 Matter is classified as a (1) substance, only (2) substance or as a mixture of substances (3) homogenous mixture, only (4) homogenous mixture or as a heterogeneous mixture | 2 | definition of matter |
| 16 Which substance can not be decomposed by a chemical change? (1) ammonia (3) propanol (2) copper (4) water | 2 | definition of an element |
| 17 A beaker contains both alcohol and water. These liquids can be separated by distillation because the liquids have different (1) boiling points (3) particle sizes (2) densities (4) solubilities | 1 | boiling points== distillation |
| 18 Which term is defined as a measure of the average kinetic energy of the particles in a sample of matter? (1) activation energy (3) temperature (2) potential energy (4) entropy | 3 | definition of temperature |
| 19 How do the boiling point and freezing point of a solution of water and calcium chloride at standard pressure compare to the boiling point and freezing point of water at standard pressure? (1) Both the freezing point and boiling point of the solution are higher. (2) Both the freezing point and boiling point of the solution are lower. (3) The freezing point of the solution is higher and the boiling point of the solution is lower. (4) The freezing point of the solution is lower and the boiling point of the solution is higher. | 4 | BP increase FP decrease |
| 20 Under which conditions of temperature and pressure does a sample of neon behave most like an ideal gas? (1) 100 K and 0.25 atm (2) 100 K and 25 atm (3) 400 K and 0.25 atm (4) 400 K and 25 atm | 3 | ideal gas=ideal vacation high temp low pressure |