Physics, Chemistry and Biology: Post your doubts here!

[exploded diper]

cn any1 plz ans thx View attachment 38906

1. 20cm3/1000=0.02 dm3/24dm3=0.00083 moles of butyne
2 mole -----> 11mole o2 .... so 0.00083--->11*0.00083/2=0.0045 moles o2
so 0.0045*24=0.11 dm3*1000=110 cm3 o2
tell me if i m right
i will answer rest later

 

[exploded diper]

2. 2 moles butyne ---> 8 mole co2
so 0.00083 ---> 8* 0.00083/2= 0.00332 moles co2
volume= o.oo332*24000=79.68 cm3 co2

 

[exploded diper]

cn any1 plz ans thx View attachment 38906

3.o2 left is 150 -110= 40 cm3
co2 left is 80 cm3
so total volume = 40 + 80 = 120 cm3

 

[Awesome12]

View attachment 38869
since x and y are parallel there resistance is less.........so when y is removed the resistance across x increeases..and so does the voltage...as x and z are arranged in series so voltage across z decreases so it becomes less brighter......brightness depends on voltage

In a voltage circuit, the voltage remains the same. Thus when we add or remove the lamp, the total voltage at X will still remain the same. As a result, Z will light with the same brightness

 

[3abder7man]

In a voltage circuit, the voltage remains the same. Thus when we add or remove the lamp, the total voltage at X will still remain the same. As a result, Z will light with the same brightness

Nope. Assume each bulb has a resistance of 2 ohms, so before Y is removed, X and Y have a combined resistance of (1/2)+(1/2) = 1 ohm
while after Y is removed X would have a resistance of 2 ohms, and so a higher voltage. Consequently, the voltage across Z will decrease and it gets dimmer

 

[eureka!]

You know what? - this idiocy had come in the paper I'd seen the answer in the MS, but i dunno... Do we have to KNOW this or DERIVE it?

Why should we be expected to know it? I mean, germanium oxide is pretty obscure. You've just gotta bank on that 'similar to SiO2' statement. Plus, the formula's the same too.

 

[Phoenix Blood]

Why should we be expected to know it? I mean, germanium oxide is pretty obscure. You've just gotta bank on that 'similar to SiO2' statement. Plus, the formula's the same too.

That's what i mean- this SiO2. Do we have to know that it's surrounded by six oxygen atoms, and the oxygen atoms are surrounded by two of it? Well, now i know it... but-
Lol. How can it be that it's surrounded by the six O2s and simultaneously two SiO2s surround this O2?
Draw and show zara

 

[Sahil_99]

paper: 0620/32/M/J/10 doubt question number 7a and 8c and 3bvi

 

[Awesome12]

Nope. Assume each bulb has a resistance of 2 ohms, so before Y is removed, X and Y have a combined resistance of (1/2)+(1/2) = 1 ohm
while after Y is removed X would have a resistance of 2 ohms, and so a higher voltage. Consequently, the voltage across Z will decrease and it gets dimmer

Thanks

 

[My Name]

Assalam-o-Alaikum.
Post your Physics, Chemistry and Biology doubts in here and members, along with me will try their best to help you out.

xperiment for proving that chlorophyll is nessasry for photosynthesis
and any good paper6 notes

 

[Lola_sweet]

anyone have 2013 october november mark scheme for biology?

 

[My Name]

anyone have 2013 october november mark scheme for biology?

i do!
get it from media fire

 

[3abder7man]

Thanks

Welcome. Always.

 

[eureka!]

That's what i mean- this SiO2. Do we have to know that it's surrounded by six oxygen atoms, and the oxygen atoms are surrounded by two of it? Well, now i know it... but-
Lol. How can it be that it's surrounded by the six O2s and simultaneously two SiO2s surround this O2?
Draw and show zara

Arey!! Who said two whole SiO2s have to surround anything? Read it again man! And yes, we have to know this.

 

[exploded diper]

4. moles of butyne reacted= 9/54=0.167 moles
since 2 moles butyne ---> 6 moles h2o
so 0.167 moles---> 6*0.167/2= 0.5 mole h2o
mass of h2o = 0.5 *( 2+16) =9 g h2o

cn any1 plz ans thx View attachment 38906

 

[rida.12.!!]

AS SALAM O ALAIKUM !!
Hi guys!!
umm..........................
can someone give me CIE IGCSE PHYSICS 0625 MAY/JUNE & OCTOBER/NOVEMBER 2013??!!
THX

 

[3abder7man]

AS SALAM O ALAIKUM !!
Hi guys!!
umm..........................
can someone give me CIE IGCSE PHYSICS 0625 MAY/JUNE & OCTOBER/NOVEMBER 2013??!!
THX

Check this for winter: http://ciestudy.blogspot.ae/2014/02/download-igcse-physics-0625-october.html

 

[rida.12.!!]

Check this for winter: http://ciestudy.blogspot.ae/2014/02/download-igcse-physics-0625-october.html

Thx a lot!!
but , can i get CIE IGCSE PHYSICS 0625 may/june 2013 as well??
plz
Thx

 

[3abder7man]

Thx a lot!!
but , can i get CIE IGCSE PHYSICS 0625 may/june 2013 as well??
plz
Thx

np
summer:
http://www.examtestprep.com/CIE/IGCSE/Physics-0625/2013/

 

[peacce]

i'm sorry but i dint get u :O