chemistry
posted by heather .
what is the density of an 84.7g sample of an unknown substance if the sample occupies 49.6cm3? what volume would be occupied by 7.75g of this same substance? PLEASE help need the answer tonight i have a test tomorrow i kind of not understand the second question. THANK YOU SO MUCH.

Density = Mass / Volume ...(1)
mass = 84.7 g
volume = 49.6 cm³
Density = ? g/cm³
Part 2:
From (1), we have
volume = mass / density
Use mass = 7.75g and density calculated above. 
part 1: 1.70 g/cm3
part 2: 4.55 cm3 
1.70

what is the density of an 8.64 g sample of an unknown substance if the sample occupies 33.4 cm3?