AQA GCSE - Unit 3 (P3,B3,C3) New specification papers.

Scroll to see replies

Veins take blood from the organs to the heart
arteries take blood from the heart to the organs
and capillaries allow substances needed by cells to be passed out of blood and substances produced by cells passes into blood

Reply 961

Captain Anonymous

Hey lolface, lets test each other on physics and chemistry today, there was enough biology yesterday.

In answer to your question an ester is made by reacting a carboxylic acid + alcohol --> ester + water
You use a acidic catalyst to speed up the reaction usually, sulfuric :wink:

Reply 962

Captain Anonymous

How do transformers work?

and what does/is a step up and step down transformer and what do they do with the voltage (pd)

Reply 963

Captain Anonymous

Original post by cycahm

correct! well done, capillaries are used for diffusion, you mentioned what happens, just make sure you say its diffusion :colondollar:

.

Explain how stents work and say what they are :rolleyes:

Reply 964

lolface32

Original post by Captain Anonymous

How do transformers work?

and what does/is a step up and step down transformer and what do they do with the voltage (pd)

I'll try and balance the both of you :eek:

A transformer works by electromagnetic induction. Here, a alternating current is passed over the primary coil which means that the magnetic field keeps changing, this change is felt by the soft core which then passes it on to the secondary coil. The changing field creates a potential difference across the secondary coil.

Why would a DC current not work in a transformer?

Reply 965

cycahm

Original post by Captain Anonymous

correct! well done, capillaries are used for diffusion, you mentioned what happens, just make sure you say its diffusion :colondollar:

.

Explain how stents work and say what they are :rolleyes:

theyre small mesh tubes inserted by surgeons when your arteries begin to narrow to keep them open
sorry you guys should do p3 and c3 ill come back when ive revised :smile:

Reply 966

mh97

Original post by lolface32

You got some catching up to do, but C3 and P3 can catch on quick so dw!

Explain the purposes of the veins, arteries, capillaries?

Veins = Carry blood to the heart. Usually carries deoxynentaged blood.
Arteries = Carry blood away from the heart. Usually caries oxygenated blood
Capillaries = Provides a blood supply to cells. Carries oxygenated and deoxygenated blood.

Reply 967

Captain Anonymous

Original post by lolface32

I'll try and balance the both of you :eek:

Correct well done, urm, Voltage in a transformer is developed only with a frequency. Since a dc supply has a zero frequency, voltage in a transformer will remain zero also. They don't change their current

Reply 968

tohaaaa

Original post by cycahm

theyre small mesh tubes inserted by surgeons when your arteries begin to narrow to keep them open
sorry you guys should do p3 and c3 ill come back when ive revised :smile:

Some C3:

Part 1:

1)Describe some characteristics of the transition elements.
2)What causes hard water? State the two types of hard water.
3)Explain how boiling removes temporary hardness.
4)Describe how an ion exchange resin works.
5)When Bromine reacts with Sodium Iodide, the bromine displaces the iodine to form Sodium Bromide + Iodine. Explain in terms of the electronic structure of the Halogens, why this occurs.
6)What type of ions to the halogens form?
7)Describe the trends shown in group 7 as you move down it.
8)Write a balanced symbol equation for the thermal decomposition of calcium hydrogencarbonate in a kettle.
9)Describe some uses of transition metals.

Hopefully they make sense/are do-able :P

Enjoy.

Reply 969

Captain Anonymous

What is the motor effect? and how does it work?

Reply 970

lolface32

Original post by Captain Anonymous

Well, you were going the right way but, you could have also mentioned electro magnetic induction, and how if the magnetic field won't keep changing, there won't be any of it!

Reply 971

Captain Anonymous

Original post by lolface32

Well, you were going the right way but, you could have also mentioned electro magnetic induction, and how if the magnetic field won't keep changing, there won't be any of it!

LOL FAIL

, ahaha

Reply 972

Captain Anonymous

Swiftly moving on.... explain why the haber process is made effeicent in producing a high yield (3 marks)

Reply 973

lolface32

Original post by Captain Anonymous

What is the motor effect? and how does it work?

The motor effect is when a force is experience on a wire carrying current in a magnetic field.
I don't get the second question?

Reply 974

lolface32

Original post by Captain Anonymous

LOL FAIL

, ahaha

Like a baws

Reply 975

Captain Anonymous

Original post by lolface32

Like a baws

ahaha you know :wink:

, explain the process of filtering water to make it safe to drink. How you make it clean

Reply 976

lolface32

Original post by Captain Anonymous

ahaha you know :wink:

, explain the process of filtering water to make it safe to drink. How you make it clean

Pass it through a mesh screen to remove sticks etc..
Then add chemicals to make solids and microbes stick to each other and fall to the bottom, it is then filtered to remove the solids. Finally chloride is added to the water to kill of bacteria.

Or you can just buy a ion exchange resin, which will exchange magnesium and calcium ions in a exchange for another ion.

Reply 977

lolface32

Give the advantages/ Dis-advantages of ultrasound, and also the uses! Don't bother describing :smile:

Reply 978

Captain Anonymous

Advantages: it produces a highly detailed image, which is 3D, ultrasound is not ionising therefore it is safe, Ultrasound scanning is noninvasive (no needles or injections) and is usually painless., Ultrasound is widely available, easy-to-use and less expensive than other imaging methods and it can distinguish between types of tissue.

Disadvantages: its expensive, not readily availiable, cannot sometimes detect some cancers

Uses: fetus check ups, removal of kidney stones