Volume is a derived unit and the unit of volume measure is the liter (L).
    1 L = 1 dm³       or      1 mL   =  1 cm³
 

Some Common SI Prefixes
Multiple	Prefix	Symbol	Example equivalents
106	mega	M	1 Mg = 1 x 106 g = 1,000,000 g
103	kilo	k	1 kg = 1 x 103 g = 1000 g
10-1	deci	d	1 g = 1 x 101 dg = 10 dg
10-2	centi	c	1 g = 1 x 102 cg = 100 cg
10-3	milli	m	1 g = 1 x 103 mg = 1000 mg
10-6	micro	m	1 g = 1 x 106 mg = 1,000,000 mg
10-9	nano	n	1 g = 1 x 109 ng = 1,000,000,000 ng
10-12	pico	p	1 g = 1 x 1012 pg = 1,000,000,000,000 pg

Rules of significant figures
A. All Non-zero digits are significant (843.47 has five sig. fig.)
B. Zeros -
    Leading zeros - not significant (zeros to the left of number; 0.0032 has two sig. fig.)
    Captured zeros - significant (zeros between non-zero numbers; 2.003 has four sig. fig.)
    Trailing or terminal zeros- significant only if number contains a decimal point, otherwise not (zeros to right of
    number; 9.0 has two sig. fig.)
C. Exact numbers - infinite number of sig. fig. (There are exactly 12 inches in 1 foot; both 12 and 1 are exact numbers
    and therefore have an infinite number of sig. fig.)

1. Multiplication/Division -
    the answer has same number of significant figures as the value in the operation with the least number of
    significant figures

          43.7 x 1.9932 = 87.1 (Correct answer has three sig. fig.)

2. Addition/Subtraction -
    the answer has same number of decimal places as the value in the operation with the least number of decimal places

             27.35
           +  1.4
             28.8        (The correct answer has three sig. fig.)

Exact numbers have no bearing on the number of sig. fig. and are not considered when determining the number of
sig. fig. in an answer.

Rounding
    If the first digit to be removed is less than 5, simply remove the unwanted digits. (6.7495 rounded to two digits
    is 6.7 because 4 is less than 5.)

    If the first digit is 5 or more, increase the preceding digit by one. (3.350 rounded to two digits is 3.4 because the
    first digit removed is 5 and 6.7938 rounded to four digits is 6.794 because 8 is greater than 5.)

1.  157.63 kg = ? g

     [157.63 kg][1 x 10³ g/1 kg] = 157630. g = 1.5763 x 10⁵ g
 

2.  23.85 mL = ? L

     [23.85 mL][1 L/1 x 10³ mL] = 0.02385 L
 

3.  65 mph = ? m/s

     [65 mi/hr][1.609 km/1 mi][1 x 10³ m/1 km][1 hr/3600 s] = 29.05138889 m/s = 29 m/s
 

Density is the ratio of mass to volume:      density = mass/volume

1.  What is the density of a sample of metal which has a mass of 118.26 g and a volume of 43.8 cm³?

     density = mass/volume = 118.26 g/43.8 cm³ = 2.7 g/cm³ = 2.70 g/cm³
 

2.  What is the volume of a sample of mercury which has a mass of 938.22 g and a density of 13.5 g/mL?

     Using the formula density = mass/volume

    [938.22 g][1 mL/13.5 g] = 69.49777778 mL = 69.5 mL