# chemistry exam- chapter 3

## 16 terms

### scientific notation

a way of writing very large numbers or very small numbers so they are easier to work wit two parts : 1 between 1-10 (not including 10) 2. powers of 10

### accuracy

the closness of a measurement to the actual true value

### precision

the closeness a series of measurements are to one another

### significant figures

all of the difits that are known, plus a last difit that is estimate. if a decimal is present, count from the pacific side starting with the first non- zero number. if a decimal is absernt, count from the atlantic side starting with the first non- zero number. addition and subtraction; measurement with the least number of decimal places determines the number of places in the answer. multiplication and division; measurement with the least number of significant figures determines the number of significant figures in your answer

### Length

meters--> symbol -m

kilogram--> kg

kelvin--> K

second-->s

mole--> mol

candela--> cd

ampere--> A

C+273

K-273

### dimensional analysis

a way to analyze and solve problems using the units or dimensions of measurements

### conversion problems

idenity known, conversion factors

### density

ration between the mass of an object and its volume. in water, if substance is less dense it will float and vice versa . Density of a subsance generally decreases as its temperture increases