Biology; Chemistry; Physics: Post your doubts here!

[Astellaz]

well its not a big deal.smile please

Insha'Allah I nd everyone else in this world would always be smiling

 

[MuslimGirl]

Insha'Allah I nd everyone else in this world would always be smiling

it is gud to see that u hav learnt usage of Mash'Allah and Insha'Allah

 

[Astellaz]

it is gud to see that u hav learnt usage of Mash'Allah and Insha'Allah

Im not sure I know it very well but thnx!!

 

[MuslimGirl]

Im not sure I know it very well but thnx!!

 

[legion]

20 Which calcium compound does not increase the pH of acidic soils?
A calcium carbonate
B calcium hydroxide
C calcium oxide
D calcium sulfate

answer AND reason please????

 

[snowbrood]

20 Which calcium compound does not increase the pH of acidic soils?
A calcium carbonate
B calcium hydroxide
C calcium oxide
D calcium sulfate

answer AND reason please????

well the answer is calcium sulfate as it is a neutral substance and does not change PH( a slight change may be noticed which is negligible) and so it is not a liming substance.when added to the soil the calcium in the gypsum(calcium sulfate) will displace Hydrogen on a clay particle. the hydrogen however would remain in the soil solution and the ph wont change because of the absence of carbonate and hydroxideWhen added to the soil, the calcium in the gypsum can displace the hydrogen on a clay particle. The hydrogen, however, woun in the soil solution and the pH would not change because of the absence of carbonate.

 

[legion]

thanku

 

[snowbrood]

hmm no problem

 

[SalmanPakRocks]

20 Which calcium compound does not increase the pH of acidic soils?
A calcium carbonate
B calcium hydroxide
C calcium oxide
D calcium sulfate

answer AND reason please????

Calcium Sulphate. D
Cuz Carbonate acid, hydroxide base,

 

[nightmaressana]

Um, guys, quick question. Cu doesnt react with water right? How does it form Cu(OH)2 then?

 

[KZW]

Cu reacts with water, but this reaction is VERY slow due to its relatively unreactive nature.

Copper left in moist air will form CuCO3 and Cu(OH)2 in a roughly 1:1 proportion..

2 Cu (s) + H2O (g) + CO2 (g) + O2 (g) → Cu(OH)2 (s) + CuCO3 (s)

 

[scouserlfc]

Um, guys, quick question. Cu doesnt react with water right? How does it form Cu(OH)2 then?

Its not a neccesity that u react the Cu with water directly u have indirect routes,Cu(OH)2 is insoluble u cud make it by Precipitation method !

 

[snowbrood]

a mutual induction is obtained by a 2 volt dc cell by switching the switch on and off continuously a compass needle is deflected momentarily what will happen if i change the 2 volt dc cell with 2 volt ac supply

 

[snowbrood]

my teacher says that fig1.a produces more current can u explain why???

 

[scouserlfc]

a mutual induction is obtained by a 2 volt dc cell by switching the switch on and off continuously a compass needle is deflected momentarily what will happen if i change the 2 volt dc cell with 2 volt ac supply

I think it will have the same effect as the first one had and u will no longer require to switch on and off plus there will be a deflection in the opposite direction when the polarity of the current changes,nothing more !

 

[scouserlfc]

my teacher says that fig1.a produces more current can u explain why???

Well i think in FIg 1.a the magnet becomes a whole and it then cuts the wire producing electricity while in b some of the lines of forces of the magnet are used up for repulsion and therefore it results in less current produced by the induction !

 

[snowbrood]

can anyone tell me where could i download britanncia gcse maths physics or chemistry

 

[scouserlfc]

i dont think u can find it anywhere this book !

 

[nightmaressana]

Cu reacts with water, but this reaction is VERY slow due to its relatively unreactive nature.

Copper left in moist air will form CuCO3 and Cu(OH)2 in a roughly 1:1 proportion..

2 Cu (s) + H2O (g) + CO2 (g) + O2 (g) → Cu(OH)2 (s) + CuCO3 (s)

thank you soooooo much!

 

[nightmaressana]

Its not a neccesity that u react the Cu with water directly u have indirect routes,Cu(OH)2 is insoluble u cud make it by Precipitation method !

thank you!