Physics, Chemistry and Biology: Post your doubts here!

[saaara]

What is the answer you found why its not bromide or iodide

because we did a test and we found that a white precipitate is formed which means its sulphate but we just suspect, since its white precipitate, that its chloride so we make the halide test and we find that no precipitate was seen so thats why its just chloride

 

[xlnc123]

Copper(II) oxide and carbon are both black solids. Copper(II) oxide reacts with dilute sulfuric
acid to form aqueous copper(II) sulfate. Carbon does not react with dilute sulfuric acid.
You are given a mixture of copper(II) oxide and carbon and access to dilute sulfuric acid.
Plan an experiment to investigate the percentage of copper(II) oxide in the mixture.

 

[rida.12.!!]

Copper(II) oxide and carbon are both black solids. Copper(II) oxide reacts with dilute sulfuric
acid to form aqueous copper(II) sulfate. Carbon does not react with dilute sulfuric acid.
You are given a mixture of copper(II) oxide and carbon and access to dilute sulfuric acid.
Plan an experiment to investigate the percentage of copper(II) oxide in the mixture.

i have the same doubt

 

[laith talal]

I have a question in chemstry paper 6 for tommrows exam :O

What is the test for sodium hydroxide solution?

 

[Mai(M4!)]

problems of an investigatory nature, possibly including suitable organic compounds
this is written in the syllabus of 2014 and i don't know what it means or what are the

experiments that include organic compounds?
as it is written possibly including suitable organic compound means there are other problems of an investigatory nature what are they???

help pleaaaaassssssssseeeee

 

[mohabxD]

Copper(II) oxide and carbon are both black solids. Copper(II) oxide reacts with dilute sulfuric
acid to form aqueous copper(II) sulfate. Carbon does not react with dilute sulfuric acid.
You are given a mixture of copper(II) oxide and carbon and access to dilute sulfuric acid.
Plan an experiment to investigate the percentage of copper(II) oxide in the mixture.


help please

 

[Mai(M4!)]

Copper(II) oxide and carbon are both black solids. Copper(II) oxide reacts with dilute sulfuric
acid to form aqueous copper(II) sulfate. Carbon does not react with dilute sulfuric acid.
You are given a mixture of copper(II) oxide and carbon and access to dilute sulfuric acid.
Plan an experiment to investigate the percentage of copper(II) oxide in the mixture.


help please

i'm not 100% sure this is right i just answered it as i think it should be if you know from which pp is it then check the ms i don't know which year is it so not sure
measure the mass of the mixture using a n electronic balance. put the mixture in a beaker then add dilute sulfuric acid using a measuring cylinder .some of the mixture will react to produce copper sulfate which is blue and the rest will be a black solid filter it then dry the residue by putting it in an evaporating dish so liquid will evaporate.measure the mass of the solid.subtract the mass of the solid from the mass of the mixture this will give the mass of copper oxide.dividing the mass of copper oxide over the mass of the mixture multiplied by 100 will give the percentage of copper oxide in the mixture.
i hope this helps

 

[xlnc123]

i'm not 100% sure this is right i just answered it as i think it should be if you know from which pp is it then check the ms i don't know which year is it so not sure
measure the mass of the mixture using a n electronic balance. put the mixture in a beaker then add dilute sulfuric acid using a measuring cylinder .some of the mixture will react to produce copper sulfate which is blue and the rest will be a black solid filter it then dry the residue by putting it in an evaporating dish so liquid will evaporate.measure the mass of the solid.subtract the mass of the solid from the mass of the mixture this will give the mass of copper oxide.dividing the mass of copper oxide over the mass of the mixture multiplied by 100 will give the percentage of copper oxide in the mixture.
i hope this helps

PAPER 61 2013 may june
http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s13_qp_61.pdf

the answer is wrong-it ignores any process of crystalization

 

[princess sofia]

Copper(II) oxide and carbon are both black solids. Copper(II) oxide reacts with dilute sulfuric
acid to form aqueous copper(II) sulfate. Carbon does not react with dilute sulfuric acid.
You are given a mixture of copper(II) oxide and carbon and access to dilute sulfuric acid.
Plan an experiment to investigate the percentage of copper(II) oxide in the mixture.


help please

1. using burette add 25cm3 H2SO4
2. than add CuO and C mxture to it and weigh it
3. provide heat
4. due to reaction , carbon remains unreacted n nt also dissolve in water
5. aqueous solution of copper sulphate is formed
6. filter and reweigh the filtrate
7. find percentage by dividing mass in (6) by mass in (2) and than multiply by 100

 

[Lola_sweet]

what is the colour of iodine: black, brown or purple?

 

[Akshajistari]

PURPLE ( at least I think so)

 

[Phoenix Blood]

20 cm cube of H2SO4 reacted with 2cm of magnesium ribbon and the temperature rise noted.
What effect on temperature would the reaction of 40 cm cube of H2SO4 with the same length of Mg ribbon have?
Awesome12

 

[Amralfa14]

the temperature will increase by double

 

[Amralfa14]

release of hydrogen gas which is flammable maybe so work in well ventillated area

 

[Phoenix Blood]

the temperature will increase by double

Why, but? There's not MORE Mg to react, is there?

 

[Phoenix Blood]

what is the problem of using 2 indicators in the same titration

Both will have a clash, showing different color changes. Btw, why do you even wanna use two? Is that a past paper question?

 

[princess sofia]

what is the type of chemical reaction between lead nitrate(aq) and lead chloride(aq)????

I Dnt thnk dat there is any type of reaction

 

[princess sofia]

yes

Which year

 

[Mai(M4!)]

problems of an investigatory nature, possibly including suitable organic compounds
this is written in the syllabus of 2014 and i don't know what it means or what are the

experiments that include organic compounds?
as it is written possibly including suitable organic compound means there are other problems of an investigatory nature what are they???

help pleaaaaassssssssseeeee

 

[princess sofia]

i meant potassuim chloride sorry

precipitation reaction