Chemistry: Post your doubts here!

[easchemistry12]

thank u

 

[ptet.chemistry]

Hello guys, if you always find chemistry P1 MCQs tricky, perhaps my step-by-step tutorial videos can help. If you like what my channel offers, please subscribe and share with friends/colleagues/relatives. It is a not-for-profit channel and I am simply a full time chemistry teacher wanting to reach out to help as many as possible.

ptet chemistry

I am Mr Onn, a chemist and a teacher. I graduated from University of Oxford, with a first class honours in Master of Chemistry (MChem), funded by the Brunei ...

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[easchemistry12]

Ms says correct answer is D can anyone please help me with justification of answer and why option A is not correct?

 

[ptet.chemistry]

If Kc increases at higher temperature, the forward reaction must have absorbed more heat energy to shift to the right. That means forward reaction is favoured. I would go for A.

IF D is correct, that would potentially mean how Kc remains constant, but that would also mean temperature cannot be changing, so I won't really think it is D.

 

[mustafa5255]

No problem

Can you help with 46.? The answer is 1 only.

 

[mustafa5255]

No problem

Can you help with 46.? The answer is 1 only.

isotopes can have more neutrons. Wouldn't that mean they'd have bigger radii?

 

[Hamnah Zahoor]

isotopes can have more neutrons. Wouldn't that mean they'd have bigger radii?

radii depends on number of electron not on number of neutron so this property remains the same

 

[BlaaDy99]

Ans is c but why plz help

 

[BlaaDy99]

Ans is c but why..

 

[mustafa5255]

Ans is c but why..

I'm not that good in chemistry, but from my understanding it cant be a,b, or d because these three properties are also present in NaCl and MgO and the question says that CsCl has a different structure than these two, so the only distinct property that CsCl has is the radii ratio.

 

[mustafa5255]

I'm not that good in chemistry, but from my understanding it cant be a,b, or d because these three properties are also present in NaCl and MgO and the question says that CsCl has a different structure than these two, so the only distinct property that CsCl has is the radii ratio.

Let me know if this helped.

 

[easchemistry12]

One mole of sulfuric acid is used to make an aqueous solution. The solution contains H2SO4
molecules, H+ ions, SO4 2– ions and HSO4– ions.
Which statements are correct?
1 The solution contains 6.02 × 1023 sulfur atoms.
2 The solution contains an exactly equal number of H+ ions and HSO4– ions.
3 One mole of SO4 2– ions contains two moles of electrons.
answer is D means only option 1 is correct. plz justify

 

[Filth1212]

Answer is 1,2 and 3 but how and what steps exactly?

 

[ptet.chemistry]

Hello fellow students, if you or someone else you know are preparing for O-Level or A-Level chemistry this October/November 2020, or sometime in the future, please check out my YouTube channel where I feature step-by-step tutorial videos on my thought processes in addressing the examination papers across the different variants of the Cambridge International curriculum.

ptet chemistry

I am Mr Onn, a chemist and a teacher. I graduated from University of Oxford, with a first class honours in Master of Chemistry (MChem), funded by the Brunei ...

www.youtube.com

Even if your zone(s) is/are set to sit for a specific variant, it never hurts to check out the same curriculum in other variants for practice. Please subscribe to the channel to support this not-for-profit endeavour. Also, please spread the words to your friends/teachers/contacts to benefit more students like yourself.

Thanks.

 

[BlaaDy99]

Let me know if this helped.

Yea thanks man

 

[Fareeha Zaheer]

First write the balanced equation.
2H2S + 3O2 ------> 2H2o + 2SO2
(Note:For AS you're not required to know this equation by heart but whenever such a question appears, there are either hints in it about the products or the products are stated explicitly. Nonetheless, you're expected to know the oxidation/combustion products of H2 and S2. )
Moles of H2S = Mass/Molar Mass = 8.65/((32.1 + 2) = 173/682
Moles of O2 = (3 x (173/682))/2 (since mole ratio H2S:O2 = 2:3 from the equation) = 519/1364
Volume = moles x 24 = (519/1364) x 24 = 9.13 dm^3

 

[Fareeha Zaheer]

Can I use H2S +3/2O2 =So2+h20
With the above equation volume is 18 dm^3

 

[ptet.chemistry]

Hi all, I have added more short tutorial videos covering specific concepts, like quick-bites with worked examples, explaining step-by-step how to proceed with calculations/explanations. These complement the longer videos that cover full past paper tutorials.

ptet chemistry

I am Mr Onn, a chemist and a teacher. I graduated from University of Oxford, with a first class honours in Master of Chemistry (MChem), funded by the Brunei ...

www.youtube.com

My videos/YouTube channel try to achieve more than just solving a paper or following mark scheme. Some have found some mistakes within, which is good. The viewers are learning! I don't usually try to correlate to mark schemes, and hey mistakes are common, but I try to minimise mine of course.

If you like my teaching style/explanations, please subscribe to the channel. Do drop comments if there are areas you wish me to cover. Learning chemistry is more than just about acing the exams. If you understand the story behind the concepts, then you will get the grades naturally.

 

[ptet.chemistry]

Hi all, I have added more short tutorial videos covering specific concepts, like quick-bites with worked examples, explaining step-by-step how to proceed with calculations/explanations. These complement the longer videos that cover full past paper tutorials.

ptet chemistry

I am Mr Onn, a chemist and a teacher. I graduated from University of Oxford, with a first class honours in Master of Chemistry (MChem), funded by the Brunei ...

www.youtube.com

My videos/YouTube channel try to achieve more than just solving a paper or following mark scheme. Some have found some mistakes within, which is good. The viewers are learning! I don't usually try to correlate to mark schemes, and hey mistakes are common, but I try to minimise mine of course.

If you like my teaching style/explanations, please subscribe to the channel. Do drop comments if there are areas you wish me to cover. Learning chemistry is more than just about acing the exams. If you understand the story behind the concepts, then you will get the grades naturally.

 

[Madina2410]

Help please