Chem Chapter 1

Base unit for distance

needs to have a number

meter

Base unit for mass

grams

base distance for volumn

liter

Precision

numbers are very close to each other but may not be close to the target

Accuracy

Closest to target value (maybe as average of all trials) but trials may not be close to target value 

Sigfigs

show accuracy of the value

Rule for nonzero

all nonzero digits are always significant

Rule for zero that are significant

• significant between 2 zeros

• trailing zero (zero AFTER a decimal)

rule for zero NOT SIGNIFICANTS

• Leading zeros: before a number

• Trailing IF no decimal

  • ex: 3570

Sigfig w/multiplication + division

answer will have the same number as the og number with the FEWEST sigfig

sigfig/ addition + subtraction

answer will have the same number as the og number with the FEWEST decimal places

exact numbers

RULES DONT COUNT

ex: 5 chairs will be 5 chairs

Micro

1,000,000 times less than base

Milli

1,000 times less than base

centi

100 times less than base ed

deci

10 times less than base

Kilo

1,000 times more than base

metric unit order

Micro → Milli → Centi → Deci → Base → Kilo

Dimensional analysis

do not count conversion

compound unit

used to relate different types of mesuremented

density

mass/volume

temperature

measure of how hot or cold

• f=1.8(Tc)+32

• k= Tc + 273