Chapt 2: Measurements In Chemistry

Front 1

define physical quantity

Back 1

a physical property that can be measured, described by both a number and a unit of defined size

-height
-volume
-temperature

Front 2

define unit

Back 2

a defined quantity used as a standard of measurement

Front 3

define SI

Back 3

unites of measurement defined by teh INternational System of Units

Front 4

define Mass

Back 4

A measure of the amount of matter in an object

Front 5

define Weight

Back 5

A measure of the gravitational force that the earth or other large body exerts on an object

Front 6

define Scientific notation

Back 6

a number expressed as the product of a number between one and ten, times the number ten raised to a power

Front 7

define Rounding off

Back 7

a procedure used for deleting nonsignificant figures

Front 8

define Factor-label method

Back 8

A problem solving procedure in which equations are set up so that unwanted units cancel and only the desired units remain

Front 9

define Conversion factor

Back 9

an expression of the numerical relationship between two units

Front 10

define Temperature

Back 10

the measure of how hot or cold an object is

Front 11

define Energy

Back 11

The capacity to do work or supply heat

Front 12

define Specific heat

Back 12

the amount of heat that will raise the temperature of one g of a substance by 1

Front 13

define Density

Back 13

The physical property that relates the mass of an object to its volume; mass per unit volume

Front 14

define Specific gravity

Back 14

the density of a substance divided by the density of water at the same temperature

Front 15

basic metric unit of temperature is

Back 15

Celsius degree

Front 16

define speed

Back 16

distance covered in a given time

m/s

Front 17

define density

Back 17

mass of a substance in a given volume

g/cm3

Front 18

define mass

Back 18

a measure of the amount of matter in an object

-can be determined by comparing the weight of the obejct to the weight of a known reference standard if at same location

Front 19

define weight

Back 19

a mesaure of the gravitational force that the earth or other large body exerts on an object

-depends on location
-when we weight we really mean that we are measuring mass by comparing two weights

Front 20

-the amoutn of matter in an object does not depend on`

Back 20

location

Front 21

note: every experimental measurement, no matter how precise, has a degree of uncertainty to it bc there's always a limit to the number of digits that can be determined

Back 21

note: to indicate the precision of a measrement, the value recorded should use all the digits known w/ certainty, plus one additional estimated digit that is usually considered un certain by pulus or minus 1

Front 22

rule 1 of sig figs

Back 22

zeros in the middle of a number are like any other digiti; they are always significant. thus 94.072 has five sig figs

Front 23

rule 2 of sig figs

Back 23

zeros at the beginning of anumber are not significant; they act only to locarte the decimal point. thus, 0.0834 cm has three sig figs, and 0.02907 mjl has four

Front 24

rule 3 of sig figs

Back 24

zeros at the end of a nuimber and after hte decimal point of significant. is is assumed that these zeros would not be shown unless they were significant. thus 138.200 m has six sig figs. if the value were known to only four sig fis, we sould rrite 138.2 m

Front 25

rule 4 of sig figs

Back 25

zeros at the end of a number and before an implied decimal point may or may not be significant. we cannot tell whether they are part of the measurement or whether they act only to locate the unwritten but implied decimal point. thus, 23,000 kg may have two, three, four, or five significant figures. adding a decimal point at the end would indicate that all five numbers are significant

Front 26

final point about sig figs

Back 26

some numbers, such as thougse obtained when counting objets and those that are poart of a definition, are exact and effectively have an unlimited number of sig fgs.

Front 27

rule one of rounding off numbers; error analysis

Back 27

in carrying out a multipication or division, the answer cannot have more sig figgs than either of the original numbers.

Front 28

rule 2 of rounding off numbers; error analysis

Back 28

in carrying out an addition or subtraction, the answer cannot have more digits after the decimal point than either of the original numbers.

ex. if you have 3.18 L of water and you add .01315 L more, you now have 3.19 L

Front 29

starting quantity x conversion factor=

Back 29

equivalent quantity

Front 30

temp in K =

Back 30

temp in C + 273.15

Front 31

temp in C=

Back 31

temp in K - 273.15

Front 32

specific heat =

Back 32

calories/g x C

Front 33

density=

Back 33

mass (g)/volume (mL or cm^3)

Front 34

specific gravitry

Back 34

density of a substance (g/mL)/density of water at the same temperature (g/mL)