Post your answers below, and we'll get an unofficial mark scheme!
Random answers: Bond energies: -1276/-1623 (some uncertainty here) Explain why: Energy needed making bonds was greater than energy released breaking bonds Balance equation: 2 and 2 somewhere Efficiency of Kettle: Hydrogencarbonate ions thermally decompose to carbonate, then react with calcium ions to product a precitipates of calcium carbonate (limescale). Limescale is a bad conductor of electricity - more energy needed to heat water Hard water cleaner q: Calcium and magnesium ions replaced by sodium and hydrogen ions Benefits of hard water: contains calcium which strengthens teeth and bones Element that has low boiling point: Flourine What happens in the mixture of gases? Ammonia is liquified, then cooled - Nitrogen and Hydrogen are recycled Specific heat capacity: 3444J (you had to use the mass of water (50g), not the 0.8g mass of fuel How is methane obtained: Natural gas Why air shouldn't be allowed in reactor: Air is a mixture of gases, the elements in air could have reacted with nitrogen and hydrogen in the reactor; wasting reactants, reducing yield. Other gases/elements entering the chamber also contaminates it. Two boiling tubes: Tube A: fizzing/effervescence because acid is dissolving calcium carbonate Tube B: calcium carbonate produced, solution goes cloudy Sentence completion: - acid catalyst, ester -Forward reaction is exothermic, so opposite reaction is endothermic Filling in boxes: white precipitate for the halide test, no change for the others What conditions are needed for highest yield of ammonia: 200 degrees, 1000 atm
Its Rb because in group 1 (alkali metals), the Boiling point and Melting Point decrease as you go down. Rb was the last Alkali Metal so its the lowest Boiling Melting/Point.
but then as you go up the group 7 table, the boiling point also decreases, with F being at the top
Phew! someone who did the same exam as me, was worried they were the same exam as some questions are similar/same. I also got 212, and 2,3,2 for balancing, thank you so much you've saved my worries
omg thank god!!! i thought i had got the exam entirely wrong. yeah i got 212 too and also 2,3,2 after twenty years of attempting to balance it
This wasn't no where near as hard as last year's paper, so don't expect low grade boundaries. Chem 1 and C2 were harder than our papers last year and that was 50/60 for A* so I predict 53/60 for A* for our unit.
This wasn't no where near as hard as last year's paper, so don't expect low grade boundaries. Chem 1 and C2 were harder than our papers last year and that was 50/60 for A* so I predict 53/60 for A* for our unit.
no it won't your actually mentally challenged if you think that, just because you think you did well dosen't mean the grade boundaries will jump up by 3 mate
no it won't your actually mentally challenged if you think that, just because you think you did well dosen't mean the grade boundaries will jump up by 3 mate
the whole country found the paper's easy, pipe down lad.
the whole country found the paper's easy, pipe down lad.
oi kid i know people who found it quite hard, and also people last year found the paper just as easy most likely the grade boundaries will be the same so hush little man
oi kid i know people who found it quite hard, and also people last year found the paper just as easy most likely the grade boundaries will be the same so hush little man
"hush" little man, seriously, i'd slap you back to your mom's uterus which I played with last night, stfu.