Chemistry MCQ thread...

[bionology]

P-3 has the largest radii because it has Gained 3 electrons. It's not a fact, it's concept based. Neither of the element has gained more electrons than P, so it has the largest radii

 

[xHazeMx]

P-3 has the largest radii because it has Gained 3 electrons. It's not a fact, it's concept based. Neither of the element has gained more electrons than P, so it has the largest radii

check the ionic radii graph for period 3 elements. it is a fact

 

[bionology]

come on, the logic behind the "fact" is this, I just cleared ur concept so that u could solve such kind of questions even if it is not mentioned in the data book

 

[xHazeMx]

lol thanks anyways

 

[Zishi]

why is the answer B ?? though the bond energy of A is higher !

B, that's why alkanes are the most useful fuels. Plus make balanced equations for combustion of each of 1 mole of them. The equation in which total number of moles of Co2 and H2O combined will be greater is B.

 

[alphabravocharlie]

Aoa. What is the answer, i think A.

 

[Zishi]

Try, and make each isomer on a piece of paper. This is the only way to solve these kind of questions.

 

[ninjas4life]

Aoa. What is the answer, i think A.

answer is c

 

[xHazeMx]

EXPLANATION ?

 

[xHazeMx]

why is it D and not B ???

 

[Anonymousx3]

EXPLANATION ?

This is how I worked it out:

2H2O ---> 2H2 + 02
Initial moles 1 0 0
Equilib. moles 0.8 0.2 0.1 total number of moles = 1.1
Mole fraction 0.8/1.1 0.2/1.1 0.1/1.1
Partial pressure (0.8/1.1) x 1 etc..

I hope that helped.

 

[xHazeMx]

EXPLANATION ?

This is how I worked it out:

2H2O ---> 2H2 + 02
Initial moles 1 0 0
Equilib. moles 0.8 0.2 0.1 total number of moles = 1.1
Mole fraction 0.8/1.1 0.2/1.1 0.1/1.1
Partial pressure (0.8/1.1) x 1 etc..

I hope that helped.

oh thx

 

[xHazeMx]

answer with explaining

 

[xHazeMx]

answer with explaining

is it D because sodium hydroxide is the most alkaline solution ? so the observations of reactions would be faster than any compound else? so it will end in a sharp point ?

 

[xHazeMx]

EXPLANATION ?

why this is not B ?????? any one can explain it ??

 

[ninjas4life]

why is the answer d?

 

[xHazeMx]

why is the answer d?

Na2CO3 will only react with acids giving CO2 and H2O

 

[Anonymousx3]

EXPLANATION ?

why this is not B ?????? any one can explain it ??

Because the number of moles at equilibrium is 1.1, not 1.0.
For Kp expressions you need the partial pressures of everything at equilibrium.
To figure out the partial pressure of something you need these equations:

partial pressure = mole fraction X total pressure
mole fraction = number of moles of a particular gas / total number of moles of gas

Now, back to the question:
We'll just assume that we start off with 1 mole of steam.
20% of it is converted to oxygen and hydrogen.
So now, at equilibrium, we have 0.80 mol of steam, 0.20 mol of hydrogen and 0.10 mol of oxygen (only 1 mole of oxygen compared to 2 moles of hydrogen and steam). In total, we have 1.10 moles of gas.
To find out the mole fractions we use the above equation, I'll just do the partial pressure of steam to make it clear for you :
mole fraction of steam = 0.80/1.10
and partial pressure of steam = mole fraction X total pressure = (0.80/1.10) X 1.0

I'm not very good at explaining and everything's a bit muddled but I hope you understood some of it.

 

[Zishi]

EXPLANATION ?

why this is not B ?????? any one can explain it ??

Because NaOH is far stronger base than MgOH. You always get a sharp end point with a string acid, and a strong base.

 

[xHazeMx]

EXPLANATION ?

why this is not B ?????? any one can explain it ??

Because NaOH is far stronger base than MgOH. You always get a sharp end point with a string acid, and a strong base.

i meant the previous question about Kp check it plz