chemisrty paper a level help

Hi, I have a few questions in regards to questions on this paper. For 4.2, I got correct but I was wondering what the reaction would be if it were the "other method", i.e. every species gains a proton. Would it just be Ti + H+ goes to Ti+ ? For 4.4, how do you do this calculation, I was really confused. For 8.2, what is this test/what topic does it come under? Many thanks https://filestore.aqa.org.uk/sample-papers-and-mark-schemes/2017/june/AQA-74051-QP-JUN17.PDF

Reply 1

username3249896

4.2 If titanium gained a proton then it would not be titanium.

4.4 Either use t is proportional to sqrt m or
use E to find d, then find t for 47Ti+

8.2 First sentence says it is about ion testing. The topic is periodicity.

(edited 4 years ago)

Reply 2

Bertybassett

can you expand on your answers a bit? For 4.2, my textbook says "sample is dissolved and pushed though nozzle at high pressure. A high voltage is applied, causing each particle to gain a H+ ion. The sample is turned into a gas made of positive ions". So each particle does gain a h+ in this method. What would the reaction be?

For 4.4 I have no clue what you mean

Original post by BobbJo

4.2 If titanium gained a proton then it would not be titanium.

4.4 Either use t is proportional to sqrt m or
use E to find the speed of the 49Ti+ ion, then find d, then find t for 47Ti+

8.2 First sentence says it is about ion testing. The topic is periodicity.

Reply 3

bree99

It would not be Ti + H+ goes to Ti+, as an element can only be that element if it has that specific number of protons and Ti has 22 so adding another would make it V. For this question it specifically asks for electron impact which is when an electron is knocked off, so the only possible solutions would be
Ti(g) --> Ti+(g) + e-
Ti(g) + e- --> Ti+ (g) + 2e-
or finally Ti(g) - e- --> Ti+ (g)

there are 2 methods to ionise and the one you are doing ("sample is dissolved and pushed though nozzle at high pressure. A high voltage is applied, causing each particle to gain a H+ ion. The sample is turned into a gas made of positive ions". So each particle does gain a h+ in this method) is electrospray which the question is not asking for, its asking for electron impact which is the method where an electron gun fires high energy electrons at the sample to knock off an electron. So you would not use a H+ for this question.

4.4. well firstly, 4.3 is very important as this is used in 4.4 when rearranging the equation.
I presume you got 8.137 x 10-26 for 4.3 as you didn't mention any problems with this.
You have been given t as 9.816 × 10−7 s, e as 1.013 × 10−13 J and you have worked out the mass of the 49Ti+ ion in 4.3 which leaves us with no value for d, so you would rearrange the original equation to d= t / square root of ( m/2e)

this comes out as d= (9.816 × 10−7 ) / square root of ( 8.137 x 10-26 / (2x1.013 × 10−13) ) which in the end equals 1.547

we then use this to work out t for 47Ti+ ion

which would be t= (1.547) x (square root of ( ((47/1000)/ L) / (2x 1.013 × 10−13) ) which comes out as t= 9.61x10-7
If this was confusing please feel free to message me and I will try and make it clearer.

8.2
for this question all I can advise is learning all the possible reactions in periodicity and all reactions you do in chemistry,

for this question we see that we have to distinguish between MgCl2 and AlCl3, when studying chemistry we understand that to distinguish if something has Mg ions in it then we usually add NaOH as it reacts and makes Mg(OH)2 which is a white ppt (we study this in the part about hydroxide and sulphate ions). We then move on to adding NaOH with AlCl3. AlCl3(aq) + 3 Na(OH)(aq) -- > Al(OH)3(s) + 3 NaCl(aq) which is a white ppt but on further addition of NaOH (exces)……. Al(OH)3(s) + OH- --> [ Al(OH)4 ]- (aq) which is colourless as the ppt dissolves, im sorry all I can say is you need to learn all possible reactions

chemisrty paper a level help

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you