Chapter 2: Measurement, Problem Solving, and the Mole Concept

Question 1

accuracy

Answer 1

A term that refers to how close a measured value is to the actual value.

Question 2

Avogrado’s number

Answer 2

The number of ¹²C atoms in exactly 12 g of ¹²C; equal to 6.0221421 x 10²³.

Question 3

calorie (cal)

Answer 3

A unit of energy defined as the amount of energy required to raise one gram of water by 1 °C; equal to 4.184 J.

Question 4

Calorie (Cal)

Answer 4

Equivalent to 1000 lowercase “c” calories. Same as kilocalorie (kcal); 1 Cal = 1 kcal = 1000 cal

Question 5

conversion factor

Answer 5

A factor used to convert between two different units; a conversion factor can be constructed from any two quantities known to be equivalent.

Question 6

density

Answer 6

The ratio of an object’s mass to its volume. It is a characteristic physical property of a substance and its substance also depends on its temperature.

Question 7

endothermic

Answer 7

Describes a process that absorbs heat from its surroundings.

Question 7

dimensional analysis

Answer 7

The use of units as a guide to solving problems.

Question 8

energy

Answer 8

The capacity to do work.

The total energy of an object is a sum of its kinetic energy and its potential energy.

Question 9

exothermic

Answer 9

Describes a process that releases heat to its surroundings.

Question 11

intensive property

Answer 11

A property such as density that is independent of the amount of a given substance.

Question 11

extensive property

Answer 11

A property that depends on the amount of a given substance, such as mass.

Question 12

joule (J)

Answer 12

The SI unit for energy: equal to 1 kg • m²/s².

Question 12

kilowatt-hour (kWh)

Answer 12

An energy unit used primarily to express large amounts of energy produces by the flow of electricity; equal to 3.60 x 10⁶ J.

Question 13

kinetic energy

Answer 13

The energy associated with motion of an object.

KE = (1/2)mv²

^{m = kg; v = m/s}

Question 15

law of conservation of energy

Answer 15

The law stating that energy can neither be created nor destroyed, only converted from one form to another.

Question 16

molar mass

Answer 16

The mass in grams of one mole of atoms of an element; numerically equivalent to the atomic mass of the element in amu.

Question 17

mole (mol)

Answer 17

A unit defined as the amount of material containing 6.0221421 x 10²³ (Avogadro’s number) particles.

Question 19

potential energy

Answer 19

The energy associated with the position or composition of an object.

Question 20

precision

Answer 20

A term that refers to how close a series of measurements are to one another or how reproducible they are.

Question 21

random error

Answer 21

Error that has equal probability of being too high or too low. Almost all measurements have some degree of random error. Random error can, with enough trials, average itself out.

Question 22

systematic error

Answer 22

Error that tends toward being consistently either too high or too low. Does not average out with repeated trials.

Question 23

thermal energy

Answer 23

A type of kinetic energy associated with the temperature of an object, arising from the motion of individual atoms or molecules in the object; see also heat.

Question 24

work

Answer 24

The result of a force acting through a distance.