Chemistry: Post your doubts here!

[A*****]

View attachment 64351 Can anyone solve this, please?

Is it B?

 

[joseph charlie]

In flooded soils, like those used for rice cultivation, the oxygen content is low. In such soils, anaerobic bacteria cause the loss of nitrogen from the soil as shown in the following sequence.

In which step is the change in oxidation number (oxidation state) of nitrogen different to the changes in the other steps?

NO3–(aq)
A
NO2–(aq)
B
NO(g)
C
N2O(g) N2(g


Please help guys

 

[Hamnah Zahoor]

In flooded soils, like those used for rice cultivation, the oxygen content is low. In such soils, anaerobic bacteria cause the loss of nitrogen from the soil as shown in the following sequence.

In which step is the change in oxidation number (oxidation state) of nitrogen different to the changes in the other steps?

NO3–(aq)
A
NO2–(aq)
B
NO(g)
C
N2O(g) N2(g


Please help guys

 

[Gouki_Destruction]

View attachment 64352

Correct, and if u want to know how to calculate oxidation no.s of elements in a compound/ion, this is how we do it :
1) let the element's unknown oxidation no. be x. In option A for example , u can form an equation. Remember, the total charge must equal 0 or the charge on the ion ( in this case -1)
equation: x+(3*-2)= -1 . Why ? 3 is the no. of oxygen bonded,O3 , and -2 is its charge . x=+6-1 . x=+5. So, N in NO3- is +5.
Follow the same steps to find charges for other compounds. Hope it helped .

 

[Kanekii]

Question from Ionic Equilibrium A2:
What is the PH of solution when 0.20 mole of Hcl is added to one dm3 of a solution containing 0.1 mol/dm3 each of CH3COOH and CH3COONa.
Ans:1
Need help with this and Thanks

 

[Gouki_Destruction]

Question from Ionic Equilibrium A2:
What is the PH of solution when 0.20 mole of Hcl is added to one dm3 of a solution containing 0.1 mol/dm3 each of CH3COOH and CH3COONa.
Ans:1
Need help with this and Thanks

Would've gladly helped , but m in AS .

 

[Tajrina Promela]

Is it B?

Yes, it’s B but how?

 

[Tajrina Promela]

Please help.

 

[Tajrina Promela]

 

[Gouki_Destruction]

View attachment 64354

Ummm the answer is B.

 

[A*****]

Yes, it’s B but how?

Just balance the equation

 

[Tajrina Promela]

Ummm the answer is B.

Yes but why is it B?

 

[Gouki_Destruction]

Yes but why is it B?

Its cz Y is acidic, and W reacts with it, indicating W is alkaline. As NH4CL was a part of the reaction, an alkaline gas ammonia ( NH3) is collected, and N2 is also produced . This could be checked by forming an equation and balancing it.

 

[emily kwong]

CAN SOMEONE PLEASE HELP ME!!

Group 1 nitrates decompose on heating to produce oxygen and metal nitrite, MNO2 (M = Na, K, Rb or Cs). When a particular Group 1 nitrate, MNO3, was heated until no further change occurred, it lost 10.85% of its mass. Calculate the Ar of M and hence identity it.

 

[emily kwong]

why does K+ have a greater ionic radius than Na+?

 

[Ebrahim12]

why does K+ have a greater ionic radius than Na+?

K+ has one more electron shell than Na+
K+: 2,8,8
Na+: 2,8
As you go down the group, both the ionic and atomic radii increase.

 

[Neurotransmitter]

In flooded soils, like those used for rice cultivation, the oxygen content is low. In such soils, anaerobic bacteria cause the loss of nitrogen from the soil as shown in the following sequence. In which step is the change in oxidation number (oxidation state) of nitrogen different to the changes in the other steps?

NO3 – (aq) A NO2 – (aq) B NO(g) C N2O(g) N2(g)


The answer is A . Please help !!!

 

[Hamnah Zahoor]

In flooded soils, like those used for rice cultivation, the oxygen content is low. In such soils, anaerobic bacteria cause the loss of nitrogen from the soil as shown in the following sequence. In which step is the change in oxidation number (oxidation state) of nitrogen different to the changes in the other steps?

NO3 – (aq) A NO2 – (aq) B NO(g) C N2O(g) N2(g)


The answer is A . Please help !!!

 

[Neurotransmitter]

Why is 2 and 3 not included? Is it because we're considering about isotopes so isotopic mass and nucleon number may be different?

 

[Ebrahim12]

Why is 2 and 3 not included? Is it because we're considering about isotopes so isotopic mass and nucleon number may be different?

Yes.
Molecular mass: sum of atomic masses of atoms in a molecule
Atomic mass: weighted average of isotopic masses
Isotopic mass: mass of isotope

(All relative to 1/12th of C-12)

The sample is going to have different stable carbon isotopes with different masses. The atomic mass derived from the sample is the weighted average of these different masses.