Physics, Chemistry and Biology: Post your doubts here!

[Manobilly]

Didnt understand.

 

[fishcook]

when a carboxylic acid reacts with bases it loses the H atom from the group COOH to become COO- and H+ ions
so 2 COOH groups have to be there then only 2 H+ ions will form.
whatever number of atoms remain from the molecular formula after the 2 COOH are the rest of the molecule.

 

[Manobilly]

Thanx

 

[thats_me]

Hi, had a doubt in chemistry
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w10_qp_33.pdf
question 5b (iv) Need a diagram to understand

I guess ill be this way

 

[AAnsarii]

because you know that tin is more reactive than copper and its cell produces a voltage of 0.5 and a zinc and copper cell produces a voltage of 1.1.
so a zinc and tin will produce 1.1-0.5=0.6 voltage

how do u noe dat u minus?

 

[imperial]

how r u supposed 2 noe dat? plz xplain, n sorry

fishcook explains it in a good way,

when a carboxylic acid reacts with bases it loses the H atom from the group COOH to become COO- and H+ ions
so 2 COOH groups have to be there then only 2 H+ ions will form.
whatever number of atoms remain from the molecular formula after the 2 COOH are the rest of the molecule.

 

[AAnsarii]

fishcook explains it in a good way,

thx

 

[imperial]

this and you need to know some general knowledge about esters

 

[fishcook]

cause in the 1st one where they use zinc and copper 1.1 voltage is produced, then they used tin and copper which only produced 0.5 voltage.
so if you use a zinc and tin which is more reactive than copper so a charge less than 1.1 voltage will be produced. so if 0.5 is produced by tin and copper, then zinc and tin will produce 1.1-0.5

 

[AAnsarii]

this and you need to know some general knowledge about esters

?

 

[kainat husain]

d- the formula of an acid is either of the type HY or H2Y.How could you find out which one is correct by using Aq.solutions of the acid and of sodium hydroxide. Assume that both solutions have the same concentration, 0.1 mol/dm3
please help!

 

[imperial]

?

what i mean that there is should be double bonded C

C=C

(generally in esters, i hope you got what i mean)

 

[AAnsarii]

d- the formula of an acid is either of the type HY or H2Y.How could you find out which one is correct by using Aq.solutions of the acid and of sodium hydroxide. Assume that both solutions have the same concentration, 0.1 mol/dm3
please help!

ppr?

 

[kainat husain]

how to write the ionic equation for this
reaction between magnesium and sulphuric acid

 

[AAnsarii]

how to write the ionic equation for this
reaction between magnesium and sulphuric acid

Mg2+ + H2SO4 = MgSO4 + 2H+
guess dat's it

 

[kainat husain]

Mg2+ + H2SO4 = MgSO4 + 2H+
guess dat's it

but this is the normal equation ig uess :/

 

[fishcook]

d- the formula of an acid is either of the type HY or H2Y.How could you find out which one is correct by using Aq.solutions of the acid and of sodium hydroxide. Assume that both solutions have the same concentration, 0.1 mol/dm3
please help!

i think you find it out by titration, using an indicator and comparing the volumes of acid used to neutralize lets say 25cm3 of NaOH
the one that uses less acid is H2Y so the one that uses more is HY... Im not sure though.

 

[kainat husain]

ppr?

O/N 2000 q5

 

[imperial]

how to write the ionic equation for this
reaction between magnesium and sulphuric acid

Mg + 2H+ > Mg+2 + H2

 

[AAnsarii]

O/N 2000 q5

sorry, link plz?