Chapter 2: Chemistry and Measurements

What are the five units of measurements?

length, time, temperature, mass and volume

What are measured numbers?

numbers obtained when measurning quantity
> ex: temperature, height

What are significant figures?

SFs are all digits including the estimated digit

What are the rules of sig figs?

1) all nonzero digits and zeros between digits are important
2) not zeros that act as placeholders before digits are important
3) zeros at the end of a decimal number are important
4) coefficient of a number written in scientific number is important
4) zero in the beginning of a decimal number is not significant
5) zero used as a placeholder in large number without decimal point is not important

What are exact numbers?

numbers obtained by counting or through definitions that compare two units + does not affect number of sig figs

tera

increase size of base unit
Symbol: T
10^12
1 Ts = 1 x 10^12 s
1 s = 1 x 10^-12 Ts

giga

increase size of base unit
Symbol: G
10^9
1 Gm = 1 x 10^9 m
1 m = 1 x 10^-9 Gm

mega

increase size of base unit
Symbol: M
10^6
1 Mg = 1 x 10^6 g
1 g = 1 x 10^-6 Mg

kilo

increase size of base unit
Symbol: k
10^3
1 kg = 1 x 10^3 g
1 g = 1 x 10^-3 kg

deci

decrease size of base unit
Symbol: d
10^-1 (0.1)
1 dm = 1 x 10^-1 m
1 m = 1 x 10 dm

centi

decrease size of base unit
Symbol: c
10^-2 (0.01)
1 cm = 10^-2 m
1 m = 100 cm

milli

decrease size of base unit
Symbol: m
10^-3 (0.001)
1 mg = 10^-3 g
1 g = 10^3 mg

micro

decrease size of base unit
Symbol: μ
10^-6
1 μg = 10^-6 g
1 g = 10^6 μg

nano

decrease size of base unit
Symbol: n
10^-9
1 nm = 10^-9 m
1 m = 10^9 nm

pico

decrease size of base unit
Symbol: p
10^-12
1 ps = 10^-12 s
1 s = 10^12 ps

How many kg and g in 1 pound (lb)?

1 lb = 0.454 kg
1 lb = 454 g

How many cm in 1 inch?

2.54 cm

What are the units for density?

g/mL
g/cm^3

mL = cm^3

What is the density for water?

1.0 g / mL

What are is the formula to find density?

mass/volume

What is a percent factor?

gives the ratio of the parts to the whole
% = (part / whole) x 100
* must use the same unit in the numerator and denominator

What is the volume by displacement method?

- a solid submerged in water displaces its own volume of water
- can determine volume of solid by calculating the volume difference from inital to after it is submerged