Biology; Chemistry; Physics: Post your doubts here!

[tdk]

Change in the direction.

But where does the force come from? In the mark scheme (November 2011, Paper 2 (5054/22)), it is written that the force is due to the friction between the Tyre and the Road Surface. But doesn't the force come from the engine of the car?

 

[Iridescent]

But where does the force come from? In the mark scheme (November 2011, Paper 2 (5054/22)), it is written that the force is due to the friction between the Tyre and the Road Surface. But doesn't the force come from the engine of the car?

The driving force comes from the engine but the force that is needed to keep the car moving in a circle comes from the friction between the road and the tires.

 

[AAAYY***]

can any help me with chemistry A3 question d

 

[Lilly2318]

PLZ GIVE ME THE BEST NOTES ON ORGANIC CHEMISTRY!

 

[Yazka Shathir]

How do we write Cuso4 in words?
Copper (ii) Sulfate?
Copper Sulfate?

And Ni(SO4)2 ?
Nickel Sulfate?
Nickel (ii) Sulfate?

 

[Yazka Shathir]

24000 cm3 of C3H8 ---> 72000 cm3 of Co2
15 cm3 of C3H8 -------- > x
x= 45 cm3 of Co2
(We use C3H8 , as its the limiting factor. We always use the limiting factor to determine the amount of products, not the one in excess.)
First we have to find how much oxygen is actually required to react with 15cm3 of Propene. After that subtract that with the given volume. You ll then get the remaining.
24000 cm3 : 120000 cm3
15 cm3 : x
x= 75 cm3 oxygen
100 -75 = 25 cm3 remaining
I hope this helped you ^_^ You don't have to show any workings here, as the question demands you for an answer worth 1 mark.

can any help me with chemistry A3 question d

 

[Ram97]

How do we write Cuso4 in words?
Copper (ii) Sulfate?
Copper Sulfate?

And Ni(SO4)2 ?
Nickel Sulfate?
Nickel (ii) Sulfate?

Copper (II) Sulphate & Nickel (II) Sulphate

 

[Jenn]

1) How many grams of solute are there in 1 mole of potassium hydroxide?
2) How many moles of solute are there in 500 cm cube of 2 mol dm cube solution?

Kindly explain?

 

[asadalam]

In ATP p.41 of Physics 5054,Q3.a question is asked relating to change in temperature after a test tube of submerged oil is removed from heating.Shouldn't it gradually decrease to room temperature?But in ms it is written:
(ii) temperature rises B1
then falls

Why does it rise?Why could it possibly rise if it has already been removed from heating?

 

[Ram97]

In ATP p.41 of Physics 5054,Q3.a question is asked relating to change in temperature after a test tube of submerged oil is removed from heating.Shouldn't it gradually decrease to room temperature?But in ms it is written:
(ii) temperature rises B1
then falls

Why does it rise?Why could it possibly rise if it has already been removed from heating?

Year???

 

[asadalam]

Year???

2013

 

[U7X0GXO]

Assalam-o-Allaikum and Hi everyone ,
hope u all are doin great !

Well as the topic says help for chemistry biology and Physics is available here that means that u can ask any mind blowing question or ask any question regarding a particular topic or ask abt any questions from Past paper or any of your text books.

I made this topic so that people dont make many posts asking abt bio,physics or chemistry individually but they can post their reply here where it can be answered with ease and the members wont have to go searching for topics to help! !

So what are u waiting for now write ur questions here !
THANKS and Bye or Allah Hafiz !

thank u sooo much!!!

 

[U7X0GXO]

In ATP p.41 of Physics 5054,Q3.a question is asked relating to change in temperature after a test tube of submerged oil is removed from heating.Shouldn't it gradually decrease to room temperature?But in ms it is written:
(ii) temperature rises B1
then falls

Why does it rise?Why could it possibly rise if it has already been removed from heating?

it could be that the density of the oil is very less. For example, mercury which much denser than oil, stops expanding even after removing from the source. for example mouth..... but as oil is so less dense, its temperature may increase and then decrease... hope it helps

 

[tdk]

The driving force comes from the engine but the force that is needed to keep the car moving in a circle comes from the friction between the road and the tires.

Could u plz explain all the energy conversions in this process?

 

[tdk]

When a cyclist cycles uphill the energy conversion is from the chemical energy in his body to Gravitational Potential Energy due to upper position on the Hill top. But as s/he moves uphill , some chemical energy is also converted to kinetic energy. But it is not mentioned in the Mark Scheme. Could u plz explain?

 

[Yazka Shathir]

In Biology, when we draw diagrams for magnification will it be a problem if we draw the line across the diagram ( to indicate where we measured the length ). As long as its not specified to draw the line as such...

 

[Yazka Shathir]

What does the marking scheme say?

When a cyclist cycles uphill the energy conversion is from the chemical energy in his body to Gravitational Potential Energy due to upper position on the Hill top. But as s/he moves uphill , some chemical energy is also converted to kinetic energy. But it is not mentioned in the Mark Scheme. Could u plz explain?

 

[Umna.Asim]

There's this experiment with eosin to check for what part of a plant transports water and solutes.
There's a question regarding it that why do you need to wash the roots thoroughly before putting it in eosin solution and before cutting it into sections. What would be its answer?

 

[Umna.Asim]

Here's a picture for the experiment

 

[Umna.Asim]

There's this experiment with eosin to check for what part of a plant transports water and solutes.
There's a question regarding it that why do you need to wash the roots thoroughly before putting it in eosin solution and before cutting it into sections. What would be its answer?