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Chemistry: Post your doubts here!

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1) In an experiment 12.0dm3 of oxygen measured under room conditions is used to burn completely 0.10mol of propan-1-ol. What is the final volume of gas measured at room conditions? ANS: 8.40dm3
Anyone can explain?
CH3CH2CH2OH + 4.5O2------>3CO2 + 4H2O
so 0.1 mol propanol reacts with 0.45 mol of the o.5 mol oxygen provided (12dm3 oxygen is 0.5 mol)
0.05 mol of oxygen is left over as gas.
0.3 mol of CO2 is formed which is the gaseous product as H2O will be liquid at r.t.p.
0.35mol of total gases.
0.35x24=8.4dm3 gases in the final mixture under ROOM CONDITIONS.
 
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Can Anyone Explain everything we need to know about Organic Analysis ( I-R Spectroscopy) for AS Level? or some links to where I could get the notes??
Or explain with some past exam question?
 
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Which reaction will give 2-chloropropane in the best yield?
A chlorine gas with propene gas in the presence of UV light
B cl2 gas with propene gas in the dark
C propan-2-ol with dil NaCl
D propan-2-ol with PCl5
The answer is D can anyone explain??
 
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31 The 1 H3 + ion was first characterised by J. J. Thomson over a century ago. 6 Li is a rare isotope of lithium which forms the 6 Li+ ion.
Which statements are correct?
1 Both ions contain the same number of protons.
2 Both ions contain the same number of electrons.
3Both ions contain the same number of neutrons.

ans is b explainnn
 
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ok
CH3CH2CH2OH + 4.5O2------>3CO2 + 4H2O
so 0.1 mol propanol reacts with 0.45 mol of the o.5 mol oxygen provided (12dm3 oxygen is 0.5 mol)
0.05 mol of oxygen is left over as gas.
0.3 mol of CO2 is formed which is the gaseous product as H2O will be liquid at r.t.p.
0.35mol of total gases.
0.35x24=8.4dm3 gases in the final mixture under ROOM CONDITIONS.

ok thx
 
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aaa.png
pls explain all briefly. Starting from part (ii)
remember Ag2SO4 partially soluble.
paper is m/j 2015 p43
Thanks!!
 
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2-x : x/2 : x

In essence, it's a pretty simple question if you ask me. People tend to get confused seeing variables instead of constants.

Anyhow.

There are two approaches to this.

One is quicker but much more confusing. If you want, let me know and I'll enlist that too.

If not, simply take the equations and manipulate.

A- Inital: 2 : 0 : 0
Final : 2-x: 2x : x
Total moles: 2-2+2x+x = 3x so A is incorrect.

B-
Initial: 2 : 0 : 0
Final: 2-2x : 2x : x
Total moles: 2-2x+2x+x = 2+x so B is incorrect

C-
Initial: 2 : 0 : 0
Final 2-2x:x:x
Total = 2-2x+x+x = 2

D-
Initial: 2 : 0 : 0
Final: 2-x : x/2 : x [x = 2R]
Total moles = 2-x+x/2+x =2+x/2 mols!

B is correct cuz the ans is 2+x...
 
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Could someone please help me with a problem on May/June 2014/P23...question #2
I am having difficulty understand (iv). It says, "Calculate the amount, in moles, of ammonium ions in the sample of the double salt'. From what I see on the marking scheme, it is saying the NH4+ react with the H+ in a 1:1 ration. I dont understand where this 1:1 ration is coming from? The only equation that is written is
NH4+ + OH- -----> NH3 + H2O

thanks
 

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Could someone please help me with a problem on May/June 2014/P23...question #2
I am having difficulty understand (iv). It says, "Calculate the amount, in moles, of ammonium ions in the sample of the double salt'. From what I see on the marking scheme, it is saying the NH4+ react with the H+ in a 1:1 ration. I dont understand where this 1:1 ration is coming from? The only equation that is written is
NH4+ + OH- -----> NH3 + H2O

thanks
 

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Apply alcohol may also be converted into propanol by using a ruthenium (IV) catalyst in water.
CH2=CHCH2OH-> CH3CH2CHO
Suggest what is unusual about this single step ?
ANS : DISPROPORTINATION HAS TAKEN PLACE
How can I know that ? Anyone can explain?
 
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