Biology; Chemistry; Physics: Post your doubts here!

[usama321]

thanks and sorry bro

NP.

 

[TheStallion-Reborn]

hmm 8 would be taking moments, the weight is acting at 30 cm mark, so

30*x = 60 *15
x=30N divide by 10 you get 3 kg

for 10, the more the area the less the pressure, so C or D (m not sure)

12 D as potential energy is decreasing and K.E is constant

13 power = energy/time

sir! i knw all tht, but my answrs r all wrong!

 

[usama321]

sir! i knw all tht, but my answrs r all wrong!

 

[TheStallion-Reborn]

4 12, isnt it c?

 

[usama321]

4 12, isnt it c?

if the K.E had been increasing, that would have been the answer. But when it is constant, it means that the energy is being lost as some other means, which in this answer is thermal energy

 

[Young Stunner]

Chemistry question please help! How to draw the metallic bond of copper.
5070/21 Jun2010 Q5 d(1)
http://papers.xtremepapers.com/CIE/...l O Level/Chemistry (5070)/5070_s10_qp_21.pdf

 

[sourov97]

Chemistry question please help! How to draw the metallic bond of copper.
5070/21 Jun2010 Q5 d(1)
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s10_qp_21.pdf

something like this....u have to show the sea of electrons (the orange ones are negative)

 

[papajohn]

Chemistry question please help! How to draw the metallic bond of copper.
5070/21 Jun2010 Q5 d(1)
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s10_qp_21.pdf

 

[papajohn]

Please anyone??

 

[sourov97]

Please anyone??View attachment 26524View attachment 26524

where is this question from?

 

[usama321]

Please anyone??View attachment 26524View attachment 26524

well my answer is D. I am not sure, but this is how i came up with it

The mass of water is 808-308 = 500g. So the volume would be mass/density = 500cm3

Now we know that the measuring cylinder has a capacity of 500 cm 3

Now the mass of the sand is 1200-308 = 892g

Mass of water in the last beaker is 1500-1200 = 300g

So volume of water in last beaker would be 300/1 = 300cm3

The rest of the volume that remains in the beaker is 500-300 = 200 cm3

now density of sand = 892/200 = 4.46 hope i am correct

 

[sourov97]

well my answer is D. I am not sure, but this is how i came up with it

The mass of water is 808-308 = 500g. So the volume would be mass/density = 500cm3

Now we know that the measuring cylinder has a capacity of 500 cm 3

Now the mass of the sand is 1200-308 = 892g

Mass of water in the last beaker is 1500-1200 = 300g

So volume of water in last beaker would be 300/1 = 300cm3

The rest of the volume that remains in the beaker is 500-300 = 200 cm3

now density of sand = 892/200 = 4.46 hope i am correct

i got this ans too.

 

[sourov97]

any has notes on the three types of steel/iron ...wrought iron, stainless steel and one other, connecting special features to their use?

 

[Suchal Riaz]

I m sure answer of mark scheme is wrong. try it and tell me the answer please:


Buland Iqbal Saad Mughal usama321 asma tareen robinhoodmustafa

 

[sourov97]

I m sure answer of mark scheme is wrong. try it and tell me the answer please:
View attachment 26529

Buland Iqbal Saad Mughal usama321 asma tareen robinhoodmustafa

is it 450 cm3 ?

 

[papajohn]

is it 450 cm3 ?

My answer too..

 

[usama321]

I m sure answer of mark scheme is wrong. try it and tell me the answer please:
View attachment 26529

Buland Iqbal Saad Mughal usama321 asma tareen robinhoodmustafa

part i ) aqueous, solid, liquid, gas

part ii) moles of HCl = 25*1.5/1000= 0.0375
moles of CO2 produced = 0.0375/2 = 0.1875*24000 = 450cm3

 

[papajohn]

So 450 cm3 must be the answer??

 

[sourov97]

any has notes on the three types of steel/iron ...wrought iron, stainless steel and one other, connecting special features to their use?

what are the conditions for hydrolysis, and fermentation?

 

[usama321]

what are the conditions for hydrolysis, and fermentation?

for fermentation of glucose, the flask should be such so that air does not enter it. Yeast as catalyst and 35 C temperature

For hydrolysis of ethene, phosphoric acid catalyst, 300 C temperature, and about 60 atmospheres (i am not sure about the pressure though)