OCR GCSE Chemistry Gateway A 9-1 UNOFFICIAL MARK SCHEME

What did you get for the metal oxides question???

Does anyone know what the answer was for the bond energy question as I got + 127?

Condense the metal oxides into its liquid form and then dissolve it in water. Then measure the pH of the solution (e.g. with a pH probe) and if the solution is alkaline, then the element was a metal.
(basically this questions tested you on if you knew that metal oxides dissolved in water produced an alkaline solution and non-metal oxides produce an acidic solution when dissolved in water)

I accidentally put 0.01 mol but as it’s 4 marks would I get 2 marks for working out?

i literally worked out 0.0999 and left it like that as the man called times up, would I get a mark for it?

Condense the metal oxides into its liquid form and then dissolve it in water. Then measure the pH of the solution (e.g. with a pH probe) and if the solution is alkaline, then the element was a metal.
(basically this questions tested you on if you knew that metal oxides dissolved in water produced an alkaline solution and non-metal oxides produce an acidic solution when dissolved in water)

or you could do qualitative analysis; flame test with bright colours or NaOH test with precipitate.

Well, fudge. I said to test for whether it was acidic

It was -400 or something. It had to be a minus number as combustion is an exothermic reaction.

How did u get -400 then?! If u used the bond energy with the double bond (which is for energy) that would be wrong as alcohols don’t have double bonds

Well, fudge. I said to test for whether it was acidic

Does anyone know what the answer was for the bond energy question as I got + 127?

Yep 0.10 is correct as the ratios of Pb and Pb(NO3)2 are the same, so just do 20.7g/207.2 to get something like 0.0999, which to 2 s.f. is 0.10

or you could do qualitative analysis; flame test with bright colours or NaOH test with precipitate.

what mark do u guys thing u got?

what did everyone get for the question where you had to calculate the mass and then say which element it was on the periodic table . I said silver

wasn't the enthalpy change like -a thousnad or something
cos the bonds had to be drawn out correctly as carbon dioxide is a double bond