CHEM AND BIO HELP AND TIPS HERE

[7ooD]

quick question in june 2007 chemistry last line in the paper where it says number of double bonds and 7 c same paper iii in ms it says con oil i didnt find it in my book wat oil is it is there others?

[Ivo]

quick question in june 2007 chemistry last line in the paper where it says number of double bonds and 7 c same paper iii in ms it says con oil i didnt find it in my book wat oil is it is there others?

d) 884g of fat reacts with 8.84*86.2=762g of iodine.

    One mole of fat reacts with 762/254=3 moles of iodine molecules.

    Number of double bonds in one molecule of fat is 3.

c) iii) Simply look at the table for the one with the lowest saturated fat, which is corn oil.

Understood, qui ou non?
   

[7ooD]

i dnt get how u got the number of double bonds and can a strong acid displace a weaker acid from its salt solution or a stronger base displace weaker base from its salt solution By the way i dnt speak paris :p

[Ivo]

i dnt get how u got the number of double bonds and can a strong acid displace a weaker acid from its salt solution or a stronger base displace weaker base from its salt solution By the way i dnt speak paris :p

In the question it says: one mole of I₂ reacts with one mole of "1 carbon-carbon double bond".

The answer you found was 3 moles of iodine molecules.  So, 3 moles reacts with 3 moles of "1 carbon-carbon double bond", so that would make 3 double bonds.

For your second question, please give an example.

[Raywin]

Hey guys, umm a doubt. In electrolysis, is the products formed at the cathode and anode influenced by whether its a concentrated or dilute solution? Like if it is a dilute solution, will the H+ ions will have more chance of going to the cathode rather than a less reactive metal say copper and likewise the other way round, a concentrated solution will have the metal going to the cathode rather than Hydrogen? Does this happen? Thanks 

[**RoRo**]

Heey,
I have a question:
How do you know that a base is soluble or not?
And to make a soluble salt, when do you use titration and when do you use the method where you add excess of the base to the acid?
Thanks a lot in advance

[Vin]

Hey guys, umm a doubt. In electrolysis, is the products formed at the cathode and anode influenced by whether its a concentrated or dilute solution? Like if it is a dilute solution, will the H+ ions will have more chance of going to the cathode rather than a less reactive metal say copper and likewise the other way round, a concentrated solution will have the metal going to the cathode rather than Hydrogen? Does this happen? Thanks 

yes, you are right...

have a look at this presentation

[Vin]

Heey,
I have a question:
How do you know that a base is soluble or not?
And to make a soluble salt, when do you use titration and when do you use the method where you add excess of the base to the acid?
Thanks a lot in advance

All Chlorides, bromides and iodides are soluble except the chloride/bromide/iodide of lead, silver and mercury.

All carbonates are insoluble except Sodium, potassium and all group 1 metals and ammonium carbonates

All hydroxides are insoluble except Sodium, potassium(All group 1 metals in general), ammonium, calcium, strontium and barium hydroxides, aq.ammonium, which are soluble.


All sulfates are soluble except the sulfates lead , barium and calcium


If you want to make a soluble salt, you must use the bases in bold^^ and ofc. an acid

If you want the acid to be reacted fully then you may use excess of a base

[Raywin]

yes, you are right...

have a look at this presentation

Thanks a lott..

[stuntjoe]

guys i have a question....... the question says that the atomic structure of substance X is shown it has 2 electrons in the first and outer shell n in the nucleus 5 proton n 6 nucleons what's the relative charge n mass of each

[Vin]

Okay the nucleus has 5 protons and 6 nucleons
so originally the atom had 5 electrons too .. and now as there are only 4 electrons the net charge is +1 as thw element has lost one electron and there is a surplus of 1 proton in the nucleus

I don't know the diagram so I am guessing that there are two atoms shown..one is neutral and one has +1 charged, so the mass remains the same as electrons have negligible mass.

(mentioning the year would help me a lot in giving an accurate answer )

[elemis]

In the question below :


Is it CONCENTRATED aqueous Rubidium Chloride ?

OR

Is it DILUTE aqueous Rubidium CHloride ?

As you know the products will differ in each case, so how do I determine which one it is

[nid404]

What does the mark scheme say?

[elemis]

What does the mark scheme say?

This is AN OLDDDDDD paper with a teacher MS that says Hydrogen and Chlorine are produced.

[$H00t!N& $t@r]

need help with s09 q5b...