Biology; Chemistry; Physics: Post your doubts here!

[Dark Destination]

It was a joke. Haha!

 

[Miral Lovato]

what is the reaction at the anode in electrolysis of aqueous copper sulphate using copper electrodes and what is the difference when carbon electrodes are used ?

 

[Miral Lovato]

what is the reaction at the anode in electrolysis of aqueous copper sulphate using copper electrodes and what is the difference when carbon electrodes are used ?

 

[Dark Destination]

what is the reaction at the anode in electrolysis of aqueous copper sulphate using copper electrodes and what is the difference when carbon electrodes are used ?

The Hydroxide ions get discharged at the anode, since there are two anions: Sulphate and Hydroxide.
Hydroxide is easier to discharge.

Oxygen gas is produced at anode.

 

[Eman Shahid]

Physics: Efficiency, how do you know which is the output energy and the input energy?
Also, what is the process of electricity generation? I know the block diagram, but not the process.

 

[Dark Destination]

Physics: Efficiency, how do you know which is the output energy and the input energy?
Also, what is the process of electricity generation? I know the block diagram, but not the process.

They'll always mention which is the output, and which is input.

Input energy = Useful output + wasted output.

So if let's say, 100 J of Electrical energy is supplied to the bulb and is being converted into 60 J of light energy.. you should know that 60 J is the useful output energy, and 40 J is the wasted output.. and 100 J the total input energy supplied to the bulb.

The process of Electricity generation depends on the type of process you are talking about.
There are various ways to generate electricity.

Hydro-electric stations use the force of moving water to spin the turbines that are connected to AC generators that generate electricity.
Solar uses the light of the sun to heat boilers and convert water to steam which is used to run the turbines.
Fossil Fuel powered stations use the heat produced from burning fossil fuels to convert water into steam, and then the steam goes up and strikes the turbines, causing them to spin. The spinning of the turbines leads to electricity generation.

The basic principle of Electricity Generation involves the AC-Generator. The AC generator involves a rotating coil placed between a magnetic field.
Now, these various power stations, there purpose is to somehow rotate this coil.. so they connect the coil to a turbine.

And using various methods; Solar, Wind, HEP, Tidal, Geo-thermal.. they make the turbines rotate, which in turn rotates the coil, and the rotation of the coil leads to change of the magnetic flux between the two magnets which induces an electric current. So Electricity is generated and transfered to the transformers which change the voltage to allow transmission to our houses, and factories and stuff.

 

[Eman Shahid]

Thank you so much. I have a few other questions as well.
1. In the physics syllabus it says, discuss the efficiency of energy conversions in common use, particularly those giving electrical output.
2. It also says that, discuss the usefulness of energy output from a number of energy conversions.
What does these two mean?

They'll always mention which is the output, and which is input.

Input energy = Useful output + wasted output.

So if let's say, 100 J of Electrical energy is supplied to the bulb and is being converted into 60 J of light energy.. you should know that 60 J is the useful output energy, and 40 J is the wasted output.. and 100 J the total input energy supplied to the bulb.

The process of Electricity generation depends on the type of process you are talking about.
There are various ways to generate electricity.

Hydro-electric stations use the force of moving water to spin the turbines that are connected to AC generators that generate electricity.
Solar uses the light of the sun to heat boilers and convert water to steam which is used to run the turbines.
Fossil Fuel powered stations use the heat produced from burning fossil fuels to convert water into steam, and then the steam goes up and strikes the turbines, causing them to spin. The spinning of the turbines leads to electricity generation.

The basic principle of Electricity Generation involves the AC-Generator. The AC generator involves a rotating coil placed between a magnetic field.
Now, these various power stations, there purpose is to somehow rotate this coil.. so they connect the coil to a turbine.

And using various methods; Solar, Wind, HEP, Tidal, Geo-thermal.. they make the turbines rotate, which in turn rotates the coil, and the rotation of the coil leads to change of the magnetic flux between the two magnets which induces an electric current. So Electricity is generated and transfered to the transformers which change the voltage to allow transmission to our houses, and factories and stuff.

 

[Eleventeener]

In the electrolysis of concentrated aqueous compounds, is Hydrogen always formed at the cathode?

 

[Dark Destination]

Thank you so much. I have a few other questions as well.
1. In the physics syllabus it says, discuss the efficiency of energy conversions in common use, particularly those giving electrical output.
2. It also says that, discuss the usefulness of energy output from a number of energy conversions.
What does these two mean?

You're welcome.

And, That's just general stuff. You should know about how a light bulb wastes energy as heat, about how the fan wastes it as heat too. And that they are not 100% efficient.

And the second one, usefulness of energy output.. it means exactly what it says. The energy output is USEFUL.
They might give you a particular example or something, and you'll have to discuss how it's useful. Though i haven't seen any specific questions like these.

 

[Dark Destination]

In the electrolysis of concentrated aqueous compounds, is Hydrogen always formed at the cathode?

Nope.

In case of Copper and Silver compounds it isn't. Copper and Silver Ions are discharged instead of Hydrogen Ions, and Hence Hydrogen is not formed at the Cathode.

 

[Qasim Hafeez]

Gus can anyone give complete note of organic chemistry? please someone?

 

[Haris Zulfiqar]

The Hydroxide ions get discharged at the anode, since there are two anions: Sulphate and Hydroxide.
Hydroxide is easier to discharge.

Oxygen gas is produced at anode.

You are doing a mistake

 

[Haris Zulfiqar]

what is the reaction at the anode in electrolysis of aqueous copper sulphate using copper electrodes and what is the difference when carbon electrodes are used ?

Cu electrodes
at cathode Cu is discharged as it is easier to discharge thus creating a deficiency of Cu ions in the solution.
So to complete this deficiency Cu anode dissolves and forms Cu ion, Oxygen is not discharged.
Reaction at cathode
Cu ion + 2e ----------- Cu
Rection at anode
Cu --------------- Cu ion + 2e
Inert electrodes
Rection is normal and anode does not take part in reaction

Hope it helps and pray for aaaaaalllllllll

 

[Alpha Destro]

Gus can anyone give complete note of organic chemistry? please someone?

Here you go

 

[Haris Zulfiqar]

I need a full conceptual answer as required in olevel
Q) Why zinc nitrate does not react with HCl ?

In the previous posts some said that nitrate has a strong bonding and does not allow zn to be displaced but i need the answer why precipitation does not take place

 

[Mahaamm]

can you please help with bio ,physics and chemistry atp for olevels

 

[Qasim Hafeez]

Here you go

Thanks alot

 

[tayyab9801]

Someone solve this please!

 

[Haris Zulfiqar]

Someone solve this please!

 

[tayyab9801]

[/
thanks