Chemistry Paper 1 Doubts Here... !

[themathshater]

the first answer :
lime

the second answer is ammonia because it is a base so it can neutralize HCL
while carbon dioxide and litmus solution cant.

the third answer :
Its A


hope it right

for da first 1 i thimk its lime
nd da second is aluminum for car bodies cuz its light nd strong
btw can u guyz help me out in 1 Q


its may june 2004 Q NO: 29 abt da dry air stuff
help will be vry much appreciated

can u post the link ??

sorry dude um new on xpf soo ull hve to search it urself da questions pretty tricky btw

 

[veteran]

guyz, I have questions (as usual ! )

Okay so here is the first Question. It is kinda difficult to explain so I attached it



Okay 2nd Question is : Which substance can neutralise hydrochloric acid ?

• Ammonia
  Carbon Dioxide
  Litmus Solution

(& why that one and not the others )

3rd Question is also attached --->

Thnx guyz for actually reading this && trying to help annoying me

1st one is lime. the second one is ammonia and the 3rd one is B

 

[emzie285]

Hey everyone,,

Can someone help plz to get answers to paper 1 for years before 2000?!

thnx in advance :wink:

 

[themathshater]

explain why sometime acid is acting as a base???
i found this question in some past papers (paper 3)
but i forgot why..

i think ur tlkin abt an amphoteric acid wich acts as both

 

[tanmaydube]

My question please....
Which mixture cab be separated by adding water, stirring and filtering?
A) barium chloride and sodium chloride
B) calcium carbonate and sodium chloride
C) copper and magnesium
D) ethane and ethene

Please explain thanks.

 

[tanmaydube]

*Can

 

[MrKiller009]

the first answer :
lime

the second answer is ammonia because it is a base so it can neutralize HCL
while carbon dioxide and litmus solution cant.

the third answer :
Its A

hey haochen, i think the third Answer is "B" not "A" because aluminium is used in food containers as it is light and resists corrosion, and you can check that answer from the syllabus here at this link http://www.xtremepapers.me/CIE/Cambridg ... y11_sy.pdf PAGE 22 , hope i helped

 

[hansbrians]

my doubt is about production of steel,
how is the production of steel from iron ?
can anyone explain it to me..
I'm so confuse bout that..
thx..

 

[Keeemoman]

It is so easy
Firstly, the impure iron and scrap steel is entered in the blast furnace
Then it is kept in good conditions such as appropriate temperature,etc(No need to know the temperature)
Then oxygen is blown through oxygen lance
Lstly after the reaction molten steel and slag are poured ffrom furnace by tilting in diffeerent directions

 

[HyDraZin3]

My question please....
Which mixture cab be separated by adding water, stirring and filtering?
A) barium chloride and sodium chloride
B) calcium carbonate and sodium chloride
C) copper and magnesium
D) ethane and ethene

Please explain thanks.

The answer is B cuz here they are asking about filtration and in filtration there has to be one insoluble and one soluble compound.In B insoluble compound is calcium carbonate and soluble one is sodium chloride so both can be separated by filtration

 

[hansbrians]

It is so easy
Firstly, the impure iron and scrap steel is entered in the blast furnace
Then it is kept in good conditions such as appropriate temperature,etc(No need to know the temperature)
Then oxygen is blown through oxygen lance
Lstly after the reaction molten steel and slag are poured ffrom furnace by tilting in diffeerent directions

thx u very much for ur help...
by the way, is the slag contain CaSiO3 ?

 

[Keeemoman]

It is so easy
Firstly, the impure iron and scrap steel is entered in the blast furnace
Then it is kept in good conditions such as appropriate temperature,etc(No need to know the temperature)
Then oxygen is blown through oxygen lance
Lstly after the reaction molten steel and slag are poured ffrom furnace by tilting in diffeerent directions

thx u very much for ur help...
by the way, is the slag contain CaSiO3 ?

Yup man
Welcome bro

 

[Yoyo1994]

Hello all, I've got a doubt that comes from October/November 2010. It is question 17, which states:

When pink crystals of cobalt(II) chloride are heated, steam is given off and the colour of the solid changes to blue.
CoCl2.6H2O (reversible reaction sign) CoCl2 + 6H2O
What happens when water is added to the blue solid?

Colour ---------- Temperature
A changes to pink ---------- decreases
B changes to pink ---------- increases
C remains blue ---------- decreases
D remains blue ---------- increases

I chose A but it seems the answer is B. I thought that it was A because when in the beginning heat was absorbed into the crystals it was endothermic and heat is increased in the crystals and decreased in the surroundings. When water is added the whole thing is reversed and it is exothermic where heat is lost to the surroundings by the crystals and the temperature in the crystals decreases and increases in the surroundings.
Now, if I thought they were referring to the surroundings I would have chosen B but they clearly asked about what happens in the crystals when they used "colour" and "temperature".
Can someone explain to me why I got this wrong? Thanks.

 

[anonymous123]

The nucleus of an atom
a) always contains neutrons
b) always contains protons and neutrons
c) always contains protons only
d) usually contains protons and neutrons

its D ryt?

 

[AStarHunter]

The nucleus of an atom
a) always contains neutrons
b) always contains protons and neutrons
c) always contains protons only
d) usually contains protons and neutrons

its D ryt?

No, it is B since the nucleus ALWAYS contains the protons and neutrons, Not USUALLY
Hope it helps

 

[AStarHunter]

guyz, why is it C and not A in Q13. in this paper ---> http://www.xtremepapers.me/CIE/inde...GCSE/0620 - Chemistry/&file=0620_s03_qp_1.pdf
thnx in advance

 

[anonymous123]

The nucleus of an atom
a) always contains neutrons
b) always contains protons and neutrons
c) always contains protons only
d) usually contains protons and neutrons

its D ryt?

No, it is B since the nucleus ALWAYS contains the protons and neutrons, Not USUALLY
Hope it helps

What about hydrogen? It has no neutron...I also thought its B but after taking hydrogen into consideration I was confused :%)

 

[AStarHunter]

The nucleus of an atom
a) always contains neutrons
b) always contains protons and neutrons
c) always contains protons only
d) usually contains protons and neutrons

its D ryt?

No, it is B since the nucleus ALWAYS contains the protons and neutrons, Not USUALLY
Hope it helps

What about hydrogen? It has no neutron...I also thought its B but after taking hydrogen into consideration I was confused :%)

ya, but remember there are 3 different isotopes of hydrogen: one has no neutron, the other has 1 neutron and the last one has 2. but they are all found in the nucleus.
Do u understand it now ? :good:

 

[anonymous123]

Brr...forget about those isotopes.We are talking about the one wid no neutron so plz...uhmm can it be C? If you read it like this There are always protons in a nucleus only and not always neutrons in the nucleus...

 

[AStarHunter]

when u put it this way, you might be right. What does the mark scheme say ?