Question

The density of water is 1.00 h/mL at 4oC. How many water molecules are present in 2.46 mL of water at this temperature? I'm really confused how to figure this out.

Answer 1

what is the formula of density?

Answer 2

d=m/v

Answer 3

good so find m

Answer 4

1.00= m/2.46 so you would divide 1.00 by 2.46...right?

Answer 5

nope
\[\sf \frac{ D }{ 1 } = \frac{ m }{ V }\]
cross multiplication same as in math

Answer 6

D is same as D/1

Answer 7

So 1.00*2.46 then?

Answer 8

giving 2.46?

Answer 9

yep

Answer 10

so that is your mass in grams now

Answer 11

now you know mass and you know that talk is about H2O which means you can calculate molecular mass of H2O using periodic table

Answer 12

thus you can find mole

Answer 13

you know the formula of mole?

Answer 14

You times the number of the element you have by the mass. So H (2*1.008) = 2.016 right?

Answer 15

And O would be (1*16.00) =16.00

Answer 16

Am I wrong?

Answer 17

yep keep goin u r right

Answer 18

16.00+2.016 =18.016

Answer 19

yep so rounding off it'll be 18

Answer 20

Yes

Answer 21

now use mole formula and find mole

Answer 22

I kinda confused on what goes where

Answer 23

mole = mass/ molecular mass

Answer 24

thanks!

Answer 25

so now you find the moles then multiply what you got by Avogadro constant

Answer 26

mol= (2.46)/(18) =.136666

Answer 27

So 8.23 x 10^22

Answer 28

Or did I do it wrong?

Answer 29

you did it right

Answer 30

Thank you for the help!

Answer 31

you are welcome :D