Chemistry paper 1 and 2

[Syed Ali]

Well, my paper went extremely well but still i am confused on some questions. I will admire your help

1. which produces hydrogen
a. calcium oxide and water
b...................
c..................
d. magnesium and steam

I was confused in these two. can you tell which one was correct

2. The two statements
(1) useful fractions are obtained by fractional distillation of petroleum
(2) the fraction with the lowest boiling point will be at the top of fractionating column

What was the answer to this

3. catalyst
a. may be inorganic or organic
b. donot take part in reaction
c......
d........

Which was the correct one?


Paper2

zinc is added to excess hcl. then sodium hydroxide is added until it is excess. Observations?

 

[UxaiR]

1. which produces hydrogen
A. metal and acid produces hydrogen .!

3. catalyst
A. (a) may be inorganic or organic.!

 

[JAMES SMITH]

Well, my paper went extremely well but still i am confused on some questions. I will admire your help

1. which produces hydrogen
a. calcium oxide and water
b...................
c..................
d. magnesium and steam (D) IS CORRECT

I was confused in these two. can you tell which one was correct

2. The two statements
(1) useful fractions are obtained by fractional distillation of petroleum
(2) the fraction with the lowest boiling point will be at the top of fractionating column

What was the answer to this A WAS THE ANSWER

3. catalyst
a. may be inorganic or organic
b. donot take part in reaction
c......
d........

Which was the correct one? (B)


Paper2

zinc is added to excess hcl. then sodium hydroxide is added until it is excess. Observations?

WHITE PPT OF ZN(OH)2 WHICH DISSOLVES COLOURLESS SOLUTION

 

[JAMES SMITH]

not destroyed by water??

 

[Azra]

hey people how was the paper? I found it great!!!!!!

 

[Micky]

Well, my paper went extremely well but still i am confused on some questions. I will admire your help

1. which produces hydrogen
a. calcium oxide and water
b...................
c..................
d. magnesium and steam

I was confused in these two. can you tell which one was correct

2. The two statements
(1) useful fractions are obtained by fractional distillation of petroleum
(2) the fraction with the lowest boiling point will be at the top of fractionating column

What was the answer to this

3. catalyst
a. may be inorganic or organic
b. donot take part in reaction
c......
d........

Which was the correct one?


Paper2

zinc is added to excess hcl. then sodium hydroxide is added until it is excess. Observations?

We arn't meant to talk about the paper till 24 hours after it, but i guess i can still talk to you about it as it says you cant talk to people who havent given the paper whereas you obviously have.

The second one's answer was A that the statement explains it and both are correct because its true that the fraction with the lowest boiling point will be at the top of fractionating column



the answer to the MCQ is d as d. magnesium and steam react to produce MgO and H2

And the catalyst one was very very stupidly tricky, I got it wrong. the answer was the it can be organic or inorganic. Catalyst do take part in the reactions which they catalyse, but are regenerated in the process. =/

for your paper 2 the observations i think were that all the Zinc would dissolve, effervescence would be produced and a colorless solution forms..then when NaOH is added,, the solution remains colorless. I AM NOT SURE but i think this is the ans.

 

[Moiz]

The answer to p2 observation is: a white precipitate of Zn(OH)2 is formed which dissolves in excess of NaOH

 

[UxaiR]

yes.!
first white precipitate would be formed which will dissolve in excess of NaOH.~

 

[sunshine]

not destroyed by water??

because it does not wet

 

[JAMES SMITH]

not destroyed by water??

because it does not wet

DOES NOT WET???? HE WAS TALKIN ABT HYDROLYSIS

 

[M.Usman Khan]

Well, my paper went extremely well but still i am confused on some questions. I will admire your help

1. which produces hydrogen
a. calcium oxide and water
b...................
c..................
d. magnesium and steam

I was confused in these two. can you tell which one was correct

2. The two statements
(1) useful fractions are obtained by fractional distillation of petroleum
(2) the fraction with the lowest boiling point will be at the top of fractionating column

What was the answer to this

3. catalyst
a. may be inorganic or organic
b. donot take part in reaction
c......
d........

Which was the correct one?


Paper2

zinc is added to excess hcl. then sodium hydroxide is added until it is excess. Observations?

the first mcq wil b d
magnesium and steam ...it had me going to until i realised that calcium oxide was already a salt waould not react with water


the satements was A....both were correct and 2 explains 1

the catylst was inorganic and organic


P2.....white percipitate would form....would dissolve in excess of NaOH....

 

[Syed Ali]

The answer to the MCQ is d as d. magnesium and steam react to produce MgO and H2

And the catalyst one was very very stupidly tricky, I got it wrong. the answer was the it can be organic or inorganic. Catalyst do take part in the reactions which they catalyse, but are regenerated in the process. =/

for your paper 2 the observations i think were that all the Zinc would dissolve, effervescence would be produced and a colorless solution forms..then when NaOH is added,, the solution remains colorless. I AM NOT SURE but i think this is the ans.

I too marked d but calcium oxide and water will also produce hydrogen. what do you say about that?

I am still not sure about the catalyst part. Can you name any organic catalyst. I donot think it is in our syllabus

 

[beststriker]

i chose that option for the catalyst which tells that it does not take part in the reaction bcoz its unchanged in the reaction..........

 

[OakMoon!]

people enzymes are organic catalyst.... i did this mcq rong... but after the paper i thought about it

 

[Syed Ali]

the first mcq wil b d
magnesium and steam ...it had me going to until i realised that calcium oxide was already a salt waould not react with water


the satements was A....both were correct and 2 explains 1

the catylst was inorganic and organic


P2.....white percipitate would form....would dissolve in excess of NaOH....

Calcium oxide is not a salt, it's a base

Besides the formation of white ppt of znoh2, I wrote that a green gas ( chlorine ) will be released. Is it right?

 

[OakMoon!]

no chlorine will not for... y wud it? it was just like the test of a cation Zn2+. But u could write that beaker will get warm as Zinc reacted with HCl first

 

[Mobeen]

Well, my paper went extremely well but still i am confused on some questions. I will admire your help

1. which produces hydrogen
a. calcium oxide and water
b...................
c..................
d. magnesium and steam

I was confused in these two. can you tell which one was correct

2. The two statements
(1) useful fractions are obtained by fractional distillation of petroleum
(2) the fraction with the lowest boiling point will be at the top of fractionating column



What was the answer to this

3. catalyst
a. may be inorganic or organic
b. donot take part in reaction
c......
d........

Which was the correct one?


Paper2

zinc is added to excess hcl. then sodium hydroxide is added until it is excess. Observations?

1. it was D .. magnesium with steam ==> MgO nd H2
2.it was A.. both statements are corect and 2 explains 1. .
3. it ws B.. they do not take part in chemical reactions .. the definition always explains this.. nd if u hav biology thn u will no tht catalysts do not take part in the reaction..

 

[allthatglitters16]

following answers are correct
magnesium and steam.

Mg + H20 ---> MgO + H2
catalysts do not take part in reactions. (remember the only catalysts we study at o levels are inorganic for example nickel, manganese, vanadium (V) oxide. etc.

 

[Mobeen]

nd wht abt the second ques.. . abt fractional distilation of crude oil..

 

[Talha]

* in papr 1 wat was da ans to ques. which askd dat if hydrocrbns hv same % by mass of hydrogen then vat vill be the same 4 them:
a --- molecular formula
b --- emperical formula
c --- structural formula
d --- molecular mass

* in paper 2 wat wer da two physicl properties of Francium nd vat was da equation for the reaction btween Francium nd water??