POST YOUR BIO AND CHEM PAPER 1 DOUBT HERE !!!!

[FATIMAH]

Fruit 1 seems spiny which would stick on the mammals fur , but fruit 2 seems wide spread Like Parachute seeds has many hairs which helps it to be carried some distance by the wind .

THANKS !!

 

[Mymuharraq]

Hey can anyone help me with this Question in Biology, I will be very grateful!
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_w05_qp_1.pdfhttp://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_w05_qp_1.pdf
Q.4 , My answer was A but I don't know why the right answer is D :/
Thank You!

You can clearly see that the flower has more than 3 petal, so it has to go to 3 then (even i get confused)

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

I think the question is missing some information, because for the aqueous sodium chloride, if it is concentrated, chlorine is produced at the anode, but if it's dilute, oxygen is produced. And sodium hydroxide is produce either way, concentrated or dilute. But molten sodium chloride only gives sodium and chlorine. Hope this helps

Assalam-o-alaikum wr wb...
well if oxyger, OH- is produced, it means that chlorine remain as the solution...i.e the solution is Sodium Chloride NOT Sodium Hydroxide..

actually....the theory behind this question (as others say) is that...once the OH- ions are discharged...the solution, sodium chloride becomes concentrated....so chlorine is discharged too, and the remaining solution is sodium hydroxide...

Hope ^that helps

 

[Skynox]

Assalam-o-alaikum wr wb...
well if oxyger, OH- is produced, it means that chlorine remain as the solution...i.e the solution is Sodium Chloride NOT Sodium Hydroxide..

actually....the theory behind this question (as others say) is that...once the OH- ions are discharged...the solution, sodium chloride becomes concentrated....so chlorine is discharged too, and the remaining solution is sodium hydroxide...

Hope ^that helps

Exactly since both cocentration of H and OH ions decreases which resmble water…

 

[Razo513]

You can clearly see that the flower has more than 3 petal, so it has to go to 3 then (even i get confused)

 

[svenas]

Consider the equation where
The more reactive halogen displaces the less reactive one.Since,iodine is nearly the least reactive so it can't displace any halogen ,except At which is rarely used,..
So X2 is Chlorine..
Consider chlorine is passed through aqueous potassium iodide,the result will be potassium chloride and iodine(in solution)..
Potassium iodide is colourless and iodine solution is yellow brown.

plz help me with this quesdtion: http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w05_qp_1.pdf
q35..
thanks!

 

[Lost_Life]

40 At each stage in a food chain, energy is lost.
What is a result of this?
A All living organisms respire.
B Food chains always begin with green plants.
C Plants are called producers and animals consumers.
D There are very few food chains with more than five organisms

why is the answer D not A....???

 

[Lost_Life]

PLZ ANYONE HERE CAN HELP ME !!!
HOW WILL WE KNOW THAT THE FIRST ONE WILL BE DISPERSE BY ANY MAMMAL AND THE SECOND ONE BY WIND ??? IS THERE ANY VISIBLE FEATURE ???

THANKS IN ADVANCE View attachment 12212

Fruit 1 is more prickly than fruit 2, so there is a high chance of fruit 1 being carried by mammals. Fruit1's stem looks sticky (grey shade) so,again, better chance for fruit 1 to stick to the animals fur....

 

[thats_me]

plz help me with this quesdtion: http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w05_qp_1.pdf
q35..
thanks!

look,
The question says that acetylene is unsaturated that means it does not have single bonds , so it cannot be A or D
C is ethanoic acid , so the answer is B (the formula for acetylene is C2H2)

 

[saroooor]

40 At each stage in a food chain, energy is lost.
What is a result of this?
A All living organisms respire.
B Food chains always begin with green plants.
C Plants are called producers and animals consumers.
D There are very few food chains with more than five organisms

why is the answer D not A....???

Energy is lost between successive food chains , so there is no high chance to have more than 5 living organisms . So because there is energy lost in ( respiration , excretion , homeastasis etc...) so D sounds more reasonable because as energy is being lost when it reaches the last trophic level there will be a very small amount of energy which cannot stand any other trophic level higher to live .So D is more Reasonable to explain At each stage in a food chain , energy is lost .

 

[saroooor]

You can clearly see that the flower has more than 3 petal, so it has to go to 3 then (even i get confused)

It has networked not parallel veins .

 

[fishcook]

anyone has answers for 1993-2004 bio

 

[Alool]

Atom X has 8 more electrons than atom Y.
Student 1 says they are in the same group.
Student 2 says they are unreactive.
Which students can be correct?
student 1 student 2
A

yes yes
B
yes no
C 
no yes
D  no no
I don't get the question so that i will solve it

 

[angel G]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_w11_qp_11.pdf
Q : 19
answer is D , but i didn't understand how !!

 

[FATIMAH]

anyone has answers for 1993-2004 bio

its there on freeexampapers.com ! check out there

 

[fishcook]

could you please explain why the answers A?
which process can convert molecules to new substances by removing hydrogen atom?
A)Displacement
B)fermentation
C)Neutralisation
D)oxidation

 

[balloonsandhighlighters]

hi i have a chemistry question

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w03_qp_1.pdf

question 8

the answer is C... i thought non metals had low m/p and b/p as that is what it says in my text book... so i chose A but thats wrong..why? thanks

also for question 15, the answer is D. The examiner said , "............This suggests that either they were
confused about endo-versus exo-thermic or about the neutrality of solution of a salt such as potassium
nitrate. "

what does he/she mean about that neutraility of solution of salt...? is there something that we need to know? For me, i thought that the pH doesn't fall because potassium nitrate is basic... am i wrong in thinking that?

THANK YOU SOOO MUCH

 

[Skynox]

could you please explain why the answers A?
which process can convert molecules to new substances by removing hydrogen atom?
A)Displacement
B)fermentation
C)Neutralisation
D)oxidation

It's definetly neutralization since neutralization is the reaction between an acid and an alkali where the alkali destroys the acidity of the acid by accepting its hydrogen ion forming salt and water...

hi i have a chemistry question

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w03_qp_1.pdf

question 8

the answer is C... i thought non metals had low m/p and b/p as that is what it says in my text book... so i chose A but thats wrong..why? thanks

also for question 15, the answer is D. The examiner said , "............This suggests that either they were
confused about endo-versus exo-thermic or about the neutrality of solution of a salt such as potassium
nitrate. "

what does he/she mean about that neutraility of solution of salt...? is there something that we need to know? For me, i thought that the pH doesn't fall because potassium nitrate is basic... am i wrong in thinking that?

THANK YOU SOOO MUCH

Okay for that number 8 he is asking about a solid non-metal ,all non metals whatever there state is don't conduct electricity so it is either A,B,or C..You are left with melting point and boiling point..To know the state of the element at room temperatures use 20 C and trying putting it between the melting and boiling point
for example
A
MP:-210 BP:-183
Defintly the 20 goes after both so it is a gas at room temperature.
For C,
MP:119 BP:149
The 20 goes before both so it is a solid
Okay for that number 15
Classifying salts as acidic,neutral,basic
A neutral

Neutral salts are formed from the reaction between a strong acid and strong base like HNO3,and KOH.

 

[thats_me]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_w11_qp_11.pdf
Q : 19
answer is D , but i didn't understand how !!

Well,
Soda lime is present to absorb carbondioxide.
The tube Y is attached to dead seeds and X is attached to germinating seeds.
Germinating seeds respire to release energy by taking in oxygen from the water, causing the level at X to rise.
The dead seeds donot and so the level Y remains same, i.e unchanged.

 

[angel G]

Well,
Soda lime is present to absorb carbondioxide.
The tube Y is attached to dead seeds and X is attached to germinating seeds.
Germinating seeds respire to release energy by taking in oxygen from the water, causing the level at X to rise.
The dead seeds donot and so the level Y remains same, i.e unchanged.

if oxygen is being used up wont the level X fall !!