Biology; Chemistry; Physics: Post your doubts here!

[funky brat]

And how burnin of coal results in formation of acid rain

Burning of coal produces sulphur dioxide. When it rains SO2 combines with rain water to form H2SO4.

 

[funky brat]

Steps involved in fractional distillation of air anyone????????C??????

1-Dust particles are removed from air.
2-Then Carbon dioxide and water is also removed because when the air is liquified, these would block the pipes. CO2 is removed by bubbling the air through an Alkali like Calcium oxide. Water is removed by passing the air through a drying agent like silica gel.
3- The air is then compressed to about 200 atm and then allowed to expand. The process of compression and expansion is continued until the temperature of the air drops to -200 C.
4- Then the liquid air is passed into a fractionating column where different gases boil off at their respective temperatures.

 

[Mahnoorfatima]

No, linear graphs need not to pass through the origin, it is only the directly propotional ones. The difference between the linear and directly propotional graph is that in graph of load against stretch, the spring initially has some length so even if for an increase of 1 Newton force, there is an increase of 1 cm in length. So this is a linear relationship, directly proptional is when force is 0 length of spring is also zero.
And for the question part you should know that black colour is not only a good absorber of a heat but a good radiator as well and shiny surfaces are poor radiators of heat. Therefore the liquid in tube A would cool down more quickly than that in tube B. The shape of the curve would be like this.

Which question's ans is this. This looks like physics. I was asking about Chemistry s question!

 

[funky brat]

Which question's ans is this. This looks like physics. I was asking about Chemistry s question!

You were asking for the graphs overall.

 

[funky brat]

Which question's ans is this. This looks like physics. I was asking about Chemistry s question!

Oh alright. I'm sorry. Kindly give the link please or post the screenshot maybe.

 

[Mahnoorfatima]

http://papers.xtremepapers.com/CIE/...l O Level/Chemistry (5070)/5070_s11_qp_42.pdf
Last part of The paper

 

[funky brat]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s11_qp_42.pdf
Last part of The paper

You would need to apply the formula for finding the concentration. If you can't get the right answer then wait I'll solve the whole question and then let you know because the answers from previous parts are needed.

 

[exploded diper]

Relay, bell and logic gates is there. I haven't even heard this rectifying thing before let alone seeing it in the book.
And yeah reed switch is also there. Do read it once.
Relay consists of two circuits that are incomplete hence the current does not flow. But when the a small current passes through the first circuit, the other circuit is completed due to magnetic effect and a greater current flows in the large circuit. Relay is used to control devices that need a large amount of current by way of wires and switches used to control small circuits. The same phenomenon occurs in the bell, magnetism is induced and circuit is completed etc.

sup man

 

[exploded diper]

I need immediate help with physics ATP. PLEASE help me about how to use a set square theres this oct nov 2002 paper 6 first question. How do you arrange it with the ruler?

hope u get it.........hehe

 

[Mahnoorfatima]

The set square hasnt repeated after 2002 btw. It's been more than 10 years I guess. It wouldnt come hopefully but still one shouldn't take risk. Though I didnot get it. Im gonna ask my sir about that.

 

[Mahnoorfatima]

Why does a vein have a larger lumen???

 

[funky brat]

Why does a vein have a larger lumen???

Because the flood flowing through it is at a lesser pressure. Hence a greater area means lesser pressure.

 

[exploded diper]

Because the flood flowing through it is at a lesser pressure. Hence a greater area means lesser pressure.

adding......to provide less resistance to the flow of blood.....

 

[Henry Colon]

Can any one please list all the topics that are not present in biology maater but are part of the cie biolgy syllabus

 

[Mahnoorfatima]

And there is a bio ATP question in which we have to confirm the presence of a substrate that is starch. Well I know the test for it. But the next part is like How could you confirm if amylase has acted on it.? cant we use the same iodine test? In 1st part it would give a positive test while in the second a negative one since amylase has acted on it??

 

[funky brat]

And there is a bio ATP question in which we have to confirm the presence of a substrate that is starch. Well I know the test for it. But the next part is like How could you confirm if amylase has acted on it.? cant we use the same iodine test? In 1st part it would give a positive test while in the second a negative one since amylase has acted on it??

If amylase has acted on it the starch must have been converted to sucrose (reducing sugar) so you can perform the benedict's test to confirm.

 

[Mahnoorfatima]

I know but can't we use the same repeated test. Now that the enzyme has acted on it and digested it, iodine test would give us a negative result as opposed to the previous part? No?

 

[funky brat]

I know but can't we use the same repeated test. Now that the enzyme has acted on it and digested it, iodine test would give us a negative result as opposed to the previous part? No?

It would but this won't even tell you exactly what has happened. If you can carry out the starch test then why not biuret or ethanol emulsion all of them would give negative results?

 

[Mahnoorfatima]

Ohhh right right. And plus why do mosquitos feed on capillaries and not artery?

 

[Awesome12]

Ohhh right right. And plus why do mosquitos feed on capillaries and not artery?

The blood pressure in capillaries is less than the b.p in arteries. As a result, the flow of blood in capillaries is slower than in arteries. Hence, mosquitos can suck more blood in a unit time in capillaries. Plus capillaries are one celled thick which allows easy penetration of the proboscis. Also capillaries are located close to the skin, whereas arteries are more deeper in the body; the proboscis is short and can easily reach the capillaries