Question

Density: A 250-mL flask and stopper have a mass of 110.525g. A 50.0-mL sample of gasoline is pipetted into a flask, giving the total mass of 146.770g. Find the density of the gasoline.

Answer 1

@genius12

Answer 2

@aaronq

Answer 3

Density is just mass/volume

Answer 4

Ok so would I do 146.770g divided by 250mL?

Answer 5

well you want just the mass of the compound

Answer 6

Or do I subtrace 146.770g - 110.525g and then divide that by 250mL?

Answer 7

yup

Answer 8

Wait for which one is yup? subtracting right? then divide?

Answer 9

think about what you are doing

Answer 10

get the mass of the gasoline and then divide it by the volume

the mass of the gasoline does not include the mass of the stopper or flask

Answer 11

Ok I think I understand that part. So 146.770-110.525 = 36.245 .......... 36.245/250 = .14498 Is that correct?

Answer 12

probably

Answer 13

where are you getting the 250mL from though

Answer 14

you can solve this just think

Answer 15

It said the 250 was the flask -->250mL

Answer 16

reread the question

Answer 17

ok ... I will try again... ok so is it 36.245g/50mL?

Answer 18

what do you think?

Answer 19

It makes for sense. :) so I would get .7249g/mL as my density?

Answer 20

yes

Answer 21

OMG Woah, I guess they put that statement in there to trick me. and it worked! :/ But thank you so much!

Answer 22

well when you read a question like this think about what the person is doing

Answer 23

Yes I will, when you told me to reread, I did and it made much more sense. I have another question. Would you mind guiding me through it. I would like to give it a try first, then can you check it?

Answer 24

there was no trickery in this question it is all just comprehension, if you dont get something reread the question

Answer 25

Its a density question

Answer 26

Sure I dont mind helping you

Answer 27

Alright thanks, So this is the question. Aluminum foil is often incorrectly termed tin foil. If the density of tin is 7.28g/cm^3, what is the thickness pf a piece of tin foil that measures 5.70 by 4.25 and has a mass of 0.655g?

Answer 28

So I know its asking for the thickness.

Answer 29

the mass (m) = 0.655g

Answer 30

oh yes, it is cm

Answer 31

same here. :)

Answer 32

this is a ratio question

Answer 33

think about it you can calculate density with the variables you have for the tin foil

Answer 34

but you are missing one variable

Answer 35

ok so, 7.28g/cm^3 = 0.655g/ (5.70)(4.25)(x)

Answer 36

YES!

Answer 37

Thats how I would set it up right?

Answer 38

thank you for not being slow

Answer 39

lol ok great!:)

Answer 40

so now I will need a sec to try this on my calculator, I will tell you what I get..

Answer 41

I assume the measurements are in units cm

Answer 42

yes

Answer 43

you should always include units so you can make sure they cancel out

Answer 44

because you know what units you want when you finish the question

Answer 45

so if you end up with some other units you know you did something wrong

Answer 46

Just some advice

Answer 47

Ok I will keep that in mind, thank you though! :)

Answer 48

Ok so I got 0.655g x 1cm^3/7.28g/cm^3 = .08997 So then .08997cm^3/(5.70 cm)(4.25 cm) =.0037??? That answer came out weird..

Answer 49

It didn't come out weird think about how thin tinfoil is

Answer 50

unless you have never seen tinfoil

Answer 51

then look it up

Answer 52

lol ha.. the number I meant, so does that mean U did it sort of right?

Answer 53

what are the units for that number?

Answer 54

And yes I have seen tinfoil :)

Answer 55

well since it is the thickness it would be cm?

Answer 56

yup go look at some tin foil and you should be convinced that 0.0037cm x 5.70 cm x 4.25 cm is a realistic volume for a sheet of tin foil

Answer 57

that stuff is paper thin

Answer 58

Ha I will ;) Well thank you for your help, you made all of this stuff so much simpler! So I am not really sure how to use this website, how do I give you an awesome medal?

Answer 59

And yes it really is very thin!

Answer 60

click the blue button

Answer 61

if you want you can fan me if you want to ask me questions in the future or just use @ then type my name immediately after to ping me

Answer 62

by ask me questions I mean send me mail readily

Answer 63

to get help with somthing idk the features on tis site are pretty easy to use

Answer 64

also make sure you close the question btw so you can open new ones

Answer 65

Ok that is great! I will most certainly be using that! :) Its my first chemistry course, so if you like chemistry your the person for me! I think I got the main navigation ways around the website but thanks! lol yes, that would be helpful! THANKS!