Please Help: "Mixed" Chem Questions.?

Question

1- A flask contains 25.0 mL of diethyl ether weighing 17.84g.What's the density of ether?

2- What's the mass of 22.7mL sample of gasoline, whose density is 0.70g/cm^3?

3- The acidic constituent in vinegar is acetic acid. A 10.0mL sample of a certain vinegar contains 501mg of acetic acid.Whats the Mass of acetic acid expressed in micrograms?

4- A water molecule has 2 hydrogen atoms,each connected to an oxygen atom.The distance between any one hydrogen atom & the oxygen atom is 0.96 Angstroms.Whats the distance in millimeters?
--
Is the formula for Mass: M= V x D?Because that's what my answers are based on.
1- Idk if I'm doing this right but I got:7.13 g/mL

2- I actually got 15.89 but using the correct amount of Significant Figures, I think I should end up with 15.

3- ? I'm trying to work it out now.
4- ? I'm trying to work this one out as well.

IDK if I'm doing these right.Can you please check what I'm doing & possibly explain the other ones to me.Thank You! = )

Answer 1

1. Let ether be called E
17. 84gE/25mLE = 0.714g/mL (three significant figures)

2. Let gasoline be called G.
22.7mLG x 0.70gG/1mLG = 16g (two significant figures)
The mL G cancel, leaving g G

3. 1 mg = 1000 mcg, so 501 mg = 501,000 mcg

4. Let an angstrom be called A
1A = 10^-8 cm = 10^-9 mm, so 0.96 x 10^-9 mm = 9.6 x 10^-10 mm

Answer 2

1 & 2 you're working correctly. For 2, the answer should have 2 significant figures because the density has only 2.

3 & 4 are just unit conversion problems...Spend some time learning your metric prefixes and their relationships with each other. Angstroms is an odd unit..you should be able to find in your book (maybe in the inside of the back cover) how it relates to something more normal....

Answer 3

I agree with ^ that guy up there, but you rounded incorrectly on #2. It should be 16 not 15