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https://www.xtremepapers.com/commun...st-your-doubts-here.9859/page-371#post-736866A2 chemistry O/N 11, variant 43
"Calculate the pH of the buffer formed when 10.0 cm3 of 0.100 mol dm–3 NaOH is added to 10.0 cm3 of 0.250 mol dm–3 CH3CO2H, whose pKa = 4.76"
How do I solve this?
View attachment 61150
oxidation number of hydrogen is +1.36 Ammonia and chlorine react in the gas phase.
8NH3 + 3Cl 2 → N2 + 6NH4Cl
Which statements are correct?
1 Ammonia behaves as a reducing agent.
2 Ammonia behaves as a base.
3 The oxidation number of the hydrogen changes.
The answer is B
I don't understand why 3 is false. Doesn't H change from +3 to +4??
oxidation number of hydrogen is +1.
There are 3 hydrogen molecules so we multiply 3 with +1 and so with 4 molecules of hydrogen 4(+1)
So oxidation number is unchanged of hydrogen
If u are learning CIE, till I know, i didnt come across any different things, may be if u learned some other board and appearing CIE A levels, till i know they do accept, as this is what sir said to me, thought its not in ms, but answers equivallent is considered.Hi guys Ive simple question,Are we allowed to explain terms like e.g orbital hybridization or something like this ..I mean definitions?
Will we be awarded marks or no marks if we explain or not explain definitions?
2nd quetsion is are marks only awarded for what a question seeks in terms of our broad understanding or are they predefined and restricted in the marks sheets? like award this 1 marks and award this 2 marks or one or whatever?
linkinpark help me out bro
Yup Cie it is,btw dudee this site is totally dead :3If u are learning CIE, till I know, i didnt come across any different things, may be if u learned some other board and appearing CIE A levels, till i know they do accept, as this is what sir said to me, thought its not in ms, but answers equivallent is considered.
Wait for others to reply u.
Agreed!Yup Cie it is,btw dudee this site is totally dead :3
Just follow the direction.How do you solve this?? Do you just add?
Can someone pls explain each statement?
The ans is D
Just follow the direction.
1. U to S + S to R = U to R = -92 + 134 = 42
2. T to S = T to U + U to S = -75 - 92 = exothermic.
3. R to T = R to S + S to U + U to T = -134 + 92 + 75 = 33.
Only 1 is correct. THus D.
Yes by looking at arrow.But how do you decide when to add and subtract? Is it in reference to where the arrows are pointing? What am i missing out?
like, -75+92 or -75-92?
For the first question:Hello, can somebody please help me solve these questions?
View attachment 61171
View attachment 61172
View attachment 61173
Thanks in advance.
Hello, can somebody please help me solve these questions?
View attachment 61171
View attachment 61172
View attachment 61173
Thanks in advance.
For the first question:
10cm3 of CS2 will burn in 30cm2 of O2 to give 10 cm3 of CO2 and 20 cm3 of SO2 (basic stoichiometry) . But we have 50cm3 of O2 which means it's an excess. 50-30=20cm3 of excess O2. So after burning out total volume will be :
10cm3 of CO2 + 20cm3 of SO2 + 20cm3 of leftover O2 = 50cm3 of gas.
When these gases are passed through NaOH which is basic, it will react with acidic gases and absorb them
CO2 and SO2 are acidic whereas O2 is neutral. So NaOH will absorb 10cm3 of CO2 + 20cm3 of SO2= 30cm3 absorbed. So leftover volume will be Total-absorbed = 50-30= 20cm3. Which makes option C correct.
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