Question

A handful of sand has a mass of 208 g and displaces a volume of 80.0 mL. What is its density? (Make sure your answer has the correct number of significant figures.)

A. 2.6 g/mL

B. 2.60 g/mL

C. 166 g/mL

D. 166.0 g/mL

Answer 1

Density is simply mass over volume, so 2.6g/mL

Answer 2

Sorry, sig figs should be 2.60 g/mL

Answer 3

Dont they mean the same thing?

Answer 4

Not necessarily. When you put down 2.60, you know that it is EXACTLY that amount because of the extra 0. When you put down 2.6, you know that it is exactly 2.6, but it could be 2.61, 2.62, 2.66, etc..... in other words, you're not sure. Sig figs show that you are positive about that extra value.