Posted by Perrie on .
1. A piece of rectangular wood that measures 3.0 cm by 6.0 cm by 4.0 cm has a mass of 80.0 grams. What is the density of the wood? Would the piece of wood float in water?
2. I threw a plastic ball in the pool for my dog to fetch. The mass of the ball was 125g. What must the volume be to have a density of 0.500 g/mL?

Chemistry 
Jai,
#1.
Recall that the density of a material is just
d = m/V
where:
m = mass
V = volume
Also, the volume of a rectangular solid is given by
V = l*w*h
where:
l = length
w = width
h = height
Substituting,
d = 80 / (3*6*4)
d = 80 / 72
d = 1.11 g / cm^3
No, it will NOT float because the density of wood is greater than density of water (which is approximately 1 g /cm^3 at standard temperature & pressure)
#2.
d = m/V
V = m/d
V = 125 / 0.5
V = 250 mL
Hope this helps~ :)