Biology; Chemistry; Physics: Post your doubts here!

[screamingskull]

now we are going off topic..
can anyone tell me how to do this...

Water at a temperature of 16 °C enters an ice-making machine and emerges as ice cubes at a
temperature of –5 °C. The melting point of ice is 0 °C.
(a) Calculate the total energy removed from 1.0 kg of water as it cools from 16 °C, changes into
ice, and then cools to –5 °C.
specific heat capacity of liquid water = 4.2 × 103 J / (kg °C)
specific latent heat of fusion of water = 3.4 × 105 J / kg
specific heat capacity of ice = 2.1 × 103 J / (kg °C)
energy

The answer which I got id 8820 J
tell me if I'm correctso i will tell you the method

 

[khizer shahab]

are you sure??

yes i think my answer is correct but better wait for more answers

 

[Spidey21]

The answer which I got id 8820 J
tell me if I'm correctso i will tell you the method

nope its not that..:|

 

[GetSomeLife]

just suggestion it is due to in solid state the bond between molecules are not much stronger than water in liquid!!!

That seems to be inaccurate.

suggest why less energy is needed to change ice into water than to change the same
mass of water into steam
this too

Because the amount of energy required by molecules to break away completely from inter-molecular forces and escape into the air in gaseous form is more (as a fact). Whereas, energy required to just dissemble the arrangement of atoms in a solid slightly is less my guess.

 

[Spidey21]

nopes !!!

lol

 

[Spidey21]

That seems to be inaccurate.


Because the amount of energy required by molecules to break away completely from inter-molecular forces and escape into the air in gaseous form is more (as a fact). Whereas, energy required to just dissemble the arrangement of atoms in a solid slightly is less my guess.

seems much better...you sure??

 

[GetSomeLife]

seems much better...you sure??

I think "my guess" means i am actually not 100 % sure and would require further experimental guidance in order to confirm the crap i wrote above

 

[Spidey21]

I think "my guess" means i am actually not 100 % sure and would require further experimental guidance in order to confirm the crap i wrote above

ok so crap writer...get me an accurate answer

 

[GetSomeLife]

ok so crap writer...get me an accurate answer

Sorry, me no take orders from crap writer fans

 

[SalmanPakRocks]

Back on topic.

 

[screamingskull]

.
can anyone tell me how to do this...

Water at a temperature of 16 °C enters an ice-making machine and emerges as ice cubes at a
temperature of –5 °C. The melting point of ice is 0 °C.
(a) Calculate the total energy removed from 1.0 kg of water as it cools from 16 °C, changes into
ice, and then cools to –5 °C.
specific heat capacity of liquid water = 4.2 × 103 J / (kg °C)
specific latent heat of fusion of water = 3.4 × 105 J / kg
specific heat capacity of ice = 2.1 × 103 J / (kg °C)
energy

Which Year's paper is it?

 

[Spidey21]

Sorry, me no take orders from crap writer fans

i am no crap writer fan...i am a water cooler distributor!! you want one??

 

[Spidey21]

Which Year's paper is it?

2011

http://www.xtremepapers.com/papers/...nal O Level/Physics (5054)/5054_s11_qp_21.pdf
doing it atm!!

 

[screamingskull]

2011

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Physics (5054)/5054_s11_qp_21.pdf
doing it atm!!

Okay I got it
The answer has to be solved in two steps
-First calculate the energy lost from converting water to ice at 0 degrees=> E=mc(T1-T2)=> 4.2x103 x 1.0kg x (16-0)=> 67200J
-Next calculate the energy lost from conversion of ice at 0 degrees to at -5 degrees=> mc(T1-T2)=>1.0kg x 2.1x103 x [0-(-5)]=> 10500J
Add them together=> 67200J+10500J=>77700J

 

[Spidey21]

Okay I got it
The answer has to be solved in two steps
-First calculate the energy lost from converting water to ice at 0 degrees=> E=mc(T1-T2)=> 4.2x103 x 0.1kg x (16-0)=> 6720J
-Next calculate the energy lost from conversion of ice at 0 degrees to at -5 degrees=> mc(T1-T2)=>0.1kg x 2.1x103 x [0-(-5)]=> 1050J
Add them together=> 6720J+1050J=>7770J

check the marking scheme the answer is something like 4.2x10^5
i think please check this is incorrect!!

 

[screamingskull]

check the marking scheme the answer is something like 4.2x10^5
i think please check this is incorrect!!

I checked the marking scheme and it says that 77700 is the correct answer if calculation is seen.

 

[Spidey21]

I checked the marking scheme and it says that 77700 is the correct answer if calculation is seen.

oh then your right...my bad i guess..
thanx btw...

 

[screamingskull]

oh then your right...my bad i guess..
thanx btw...

Np

 

[Spidey21]

Np

 

[Mayedah]

Np

Btw doesnt the mark scheme says the final answer is 4.2 x 10^5