You are Here: Home

# AS question

Announcements Posted on
Four hours left to win £100 of Amazon vouchers!! Don't miss out! Take our short survey to enter 24-10-2016
1. When 0.28g of a basic oxide, MO, is reacted with 250cm3 of 0.05moldm–3 hydrochloricacid the excess acid required 50cm3 of 0.05moldm–3 sodium hydroxide solution forneutralisation. Which one of the following is the relative atomic mass of M?
I ended up getting 56 for the RAM but it was wrong.

Can anyone help?
Also, did you minus 16 for the oxygen on the oxide?
2. (Original post by ozmo19)
1. When 0.28g of a basic oxide, MO, is reacted with 250cm3 of 0.05moldm–3 hydrochloricacid the excess acid required 50cm3 of 0.05moldm–3 sodium hydroxide solution forneutralisation. Which one of the following is the relative atomic mass of M?
I ended up getting 56 for the RAM but it was wrong.

Can anyone help?
Are you given a balanced equation at all?

And what is the actual answer given? Could it be that you didnt subtract 16 (Mr of Oxygen) from the 56?
3. (Original post by derpz)
Are you given a balanced equation at all?

And what is the actual answer given? Could it be that you didnt subtract 16 (Mr of Oxygen) from the 56?
The answer was 40.. after all the working out it looks like i forgot to -16.

Thanks
4. (Original post by MrFartFace)
Also, did you minus 16 for the oxygen on the oxide?
(Original post by derpz)
Are you given a balanced equation at all?

And what is the actual answer given? Could it be that you didnt subtract 16 (Mr of Oxygen) from the 56?
1. 3.12 g of MCl2 were dissolved in water and made up to one litre of solution. 25.0 cm3 of thissolution reacts with 7.5cm3 of 0.100M silver nitrate solution.
Which group 2 element is M?

The answer is Barium and i not sure how to find that?
5. (Original post by ozmo19)
1. 3.12 g of MCl2 were dissolved in water and made up to one litre of solution. 25.0 cm3 of thissolution reacts with 7.5cm3 of 0.100M silver nitrate solution.
Which group 2 element is M?

The answer is Barium and i not sure how to find that?
I'll have a go, is it 0.100moles or is that the concentration? Also, are you given an equation?
6. Hi! I was looking at electronic configuration of chromium . I wanted to know why is last electon in s subshell, when d have only 5 electrons, having a capacity of 10.
7. (Original post by Noshervan)
Hi! I was looking at electronic configuration of chromium . I wanted to know why is last electon in s subshell, when d have only 5 electrons, having a capacity of 10.

http://www.chemguide.co.uk/atoms/pro...oblem.html#top
8. (Original post by Noshervan)
Hi! I was looking at electronic configuration of chromium . I wanted to know why is last electon in s subshell, when d have only 5 electrons, having a capacity of 10.
Chromium and Copper are anomalies when it comes to electronic arrangement, one of their electrons from the d sublevel is donated to the s sublevel which is known as "electron promotion" - this only occurs with Copper and Chromium!
9. (Original post by derpz)
Chromium and Copper are anomalies when it comes to electronic arrangement, one of their electrons from the d sublevel is donated to the s sublevel which is known as "electron promotion" - this only occurs with Copper and Chromium!
4s fills before the 3d, at least at this level. With the exception of copper and chromium the transition metals in that row have 2 electrons in the 4s
10. (Original post by derpz)
Chromium and Copper are anomalies when it comes to electronic arrangement, one of their electrons from the d sublevel is donated to the s sublevel which is known as "electron promotion" - this only occurs with Copper and Chromium!
They are not really anomalies. If you read the article in the link that I posted it all becomes clear. There is no 'electron promotion'. The 4s1 is the lowest energy electron configuration for that metal. Other d-block metals in the other periods do this too.
11. (Original post by samb1234)
4s fills before the 3d, at least at this level. With the exception of copper and chromium the transition metals in that row have 2 electrons in the 4s
12. (Original post by TeachChemistry)
I know, its not what really is going on but tbh for the sort of questions they ask at a level the explanation they give for things like chromium and copper is the same explanation that appears on the mark schemes, so unfortunately even though its not really true just have to go along with it to a certain extent

13. Thanks for the link, problem solved.
14. (Original post by ozmo19)
1. When 0.28g of a basic oxide, MO, is reacted with 250cm3 of 0.05moldm–3 hydrochloricacid the excess acid required 50cm3 of 0.05moldm–3 sodium hydroxide solution forneutralisation. Which one of the following is the relative atomic mass of M?
I ended up getting 56 for the RAM but it was wrong.

Can anyone help?
15. (Original post by ozmo19)
1. 3.12 g of MCl2 were dissolved in water and made up to one litre of solution. 25.0 cm3 of thissolution reacts with 7.5cm3 of 0.100M silver nitrate solution.
Which group 2 element is M?

The answer is Barium and i not sure how to find that?
16. HI! i just saw a question what is the observation when sulphuric acid is added to potassium chloride and the fumes made are passed through potasium iodide solution. the answer is a colorles solution forms. i want to ask why doesn`t the chlorine in HCl produced displace iodine in potasium iodide and form a brown solution.
17. (Original post by Noshervan)
HI! i just saw a question what is the observation when sulphuric acid is added to potassium chloride and the fumes made are passed through potasium iodide solution. the answer is a colorles solution forms. i want to ask why doesn`t the chlorine in HCl produced displace iodine in potasium iodide and form a brown solution.
Because it's not chlorine it's chloride.
18. (Original post by TeachChemistry)
Because it's not chlorine it's chloride.
But chloride ion is more reaxtive than iodide ion and it should displace iodine from potassium iodide
19. (Original post by Noshervan)
But chloride ion is more reaxtive than iodide ion and it should displace iodine from potassium iodide
Chlorine is more reactive than iodine.

Chloride is not more reactive than iodide.

Chlorine would react with iodide to give chloride and iodine. But you do not have chlorine - you have chloride.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: April 21, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### Who is getting a uni offer this half term?

Find out which unis are hot off the mark here

### How to get a 1st class degree

Poll
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.