Chem help questions

Lucky10

Can anyone help me with these questions

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Reply 1

greentron6

Where are the questions?

Reply 2

username1801813

Original post by Lucky10

Can anyone help me with these questions

you didn't attach the questions properly. There are no pictures we can see.

Reply 3

lmaooome

google it x
nah jks
where are the questions???

Use PV=nRT to get n
Calculate Mr from Mass = Mr X Moles

Attachment not found

Attachment not found

-Ideal gas equation for the first question, re-arrange pV=nRT to find n. Have a go first and then check the spoiler.
once you find n you rearrange M=MrxN to find Mr, you should know how to do this.

I cba doing all of your homework for you so if there's anything in particular you need help with shout me.

Spoiler

Reply 9

username1801813

Original post by Lucky10

I have no idea my answer came out all wrong for that??

okay then, learn these rearrangements for the ideal gas equation.
1-P=nRT/V
2-V=nRT/p
3-you already know n now
4-R is always 8.314
5-T=pV/nR

Reply 10

Lucky10

Original post by hamzakalinle

okay then, learn these rearrangements for the ideal gas equation.
1-P=nRT/V
2-V=nRT/p
3-you already know n now
4-R is always 8.314
5-T=pV/nR

I got it now, could you help on the question on y is an organic compound

Reply 11

username1973239

The equation with ethane and bromine one, have you done radical substitution?

Reply 12

Lucky10

Original post by TSlayerr

The equation with ethane and bromine one, have you done radical substitution?

I've done that one it's the next one

Reply 13

username1973239

Original post by Lucky10

I've done that one it's the next one

Wouldnt you find the moles of h2o and co2 to find out the amount carbon and hydrogen (in moles)

y+o2 ---> h20+co2 assuming its complete combustion

Reply 14

username1973239

If you want me to, I can do the calculation on paper and send you a pic of it

Reply 15

Lucky10

Original post by TSlayerr

Wouldnt you find the moles of h2o and co2 to find out the amount carbon and hydrogen (in moles)

y+o2 ---> h20+co2 assuming its complete combustion

I'm not sure, could you work it out?

Reply 16

username1973239

Original post by Lucky10

I'm not sure, could you work it out?

I want to lead you into the right direction instead of me telling you the answer.

y=0.815g
co2=2.086g
h20=0.851g

1)Find the moles of h2o
2)Find the moles of hydrogen from 1) (let me know if you dont know how to do this)
3)Find the moles of co2
4)Find the moles of carbon from 3) (let me know if you dont know how to do this)

Reply 17

username1973239

Original post by Lucky10

I'm not sure, could you work it out?

5)Find mass of hydrogen
6)Find mass of carbon
7)mass of hydrogen+carbon
8)0.815-mass of 7)
8)This mass is mass of oxygen
Let me know if you need help with empirical calc. :smile:

(edited 6 years ago)

Reply 18

Lucky10

Original post by TSlayerr

I'm kinda confused on the whole process

Reply 19

username1973239

Original post by Lucky10

I'm kinda confused on the whole process

Finding the moles of water will tell us the moles of hydrogen that has combusted from the hydrocarbon.
This is the same case with co2.
I will upload a pic going through the steps.