OCR GATEWAY CHEMISTRY B 16th June C4 C5 C6

Reply 20

EastGuava

11

Original post by heench

and for one of the questions i got 72? :/

That was the relative formula mass of a compound but I don't think it was the answer

Reply 21

heench

OP

Original post by mikyyyyy

that table which u had to estimate the answer

oh yeah, ahh i cant remember what i put. I think i did roughly 3x the melting point for the last element. Cause the no. of protons was 11 for the element that were asking us to predict, and the last element had proton number of 37, so i did abit less than 3x bigger

Reply 22

heench

OP

Original post by EastGuava

That was the relative formula mass of a compound but I don't think it was the answer

hmm i had a feeling i wasnt doing the right thing. It was only one mark? I just added them up. What did you do/get?

Reply 23

robzwolf

2

Original post by heench

hmm i had a feeling i wasnt doing the right thing. It was only one mark? I just added them up. What did you do/get?

It was one mark, and the answer was 72!

Reply 24

EastGuava

11

Okay I calculated 72 and wrote it in the method part but left the answer blank because I thought it was asking something else... great :P

Reply 25

Darcy1

12

For that collecting water prediction, did you guys say that her prediction of water made was directly proportional to the amount heated was correct?

Reply 26

StealthHawk97

1

To a certain extent because the last experiment didn't follow the trend but I said that could have been an anomaly anyway. :biggrin:

Reply 27

heench

OP

Original post by StealthHawk97

To a certain extent because the last experiment didn't follow the trend but I said that could have been an anomaly anyway. :biggrin:

yeah i put that the first few experiments supported it but not the last so she's not correct

Reply 28

mikyyyyy

how many marks was that quistion

Reply 29

mikyyyyy

for the first 6 marker i put
the top number which was the relative atomic mass is the number of protons and neutrons and can be used to work out the number of neutrons. this is done by taking away the bottom number from the top number to give the amount of neutrons. the amount of electrons are calculated by looking at the number of protons, it is always going to be the same as the number of protons.
how many marks?

Reply 30

heench

OP

Original post by mikyyyyy

for the first 6 marker i put
the top number which was the relative atomic mass is the number of protons and neutrons and can be used to work out the number of neutrons. this is done by taking away the bottom number from the top number to give the amount of neutrons. the amount of electrons are calculated by looking at the number of protons, it is always going to be the same as the number of protons.
how many marks?

id say around 2/3 because you havent talked about its place in the periodic table or the electron configuration structure :smile:

Reply 31

azaaza

For the second 6 market you didn't even need to talk about concentration

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Reply 32

Darcy1

12

Original post by azaaza

For the second 6 market you didn't even need to talk about concentration

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I swear it asked at the end how adding more reactants will change equilibrium, thats concentration

Reply 33

mikyyyyy

yeah it did i said that an increase in con would mean its more squashed the particles an increase in speed of yield also the temp dosnt affect the yield only the speed and the pressure affects the yield increase in pressure increases the amount of yield .

Reply 34

Darcy1

12

Original post by mikyyyyy

yeah it did i said that an increase in con would mean its more squashed the particles an increase in speed of yield also the temp dosnt affect the yield only the speed and the pressure affects the yield increase in pressure increases the amount of yield .

Temperature did affect the yield because the higher the temperature got the lower the yield got

Reply 35

mikyyyyy

no it dosnt it speeds up the reaction but dosnt affect the yield produced

Reply 36

cmcw

Original post by mikyyyyy

no it dosnt it speeds up the reaction but dosnt affect the yield produced

as the forward reaction is exothermic, an increase in temperature causes equilibrium to move in the endothermic direction (towards the reactants) to take in more heat - so an increase in temperature causes a increase in the amount of reactants and a decrease in the amount of product, decreasing the percentage yield

Reply 37

azaaza

I think that the more reactants was about the equilibrium shifting to the right and how the products counter by making the product faster

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Reply 38

azaaza

1) Increase temp- Decrease yield, faster rate of reaction, favours the endotheromic (reverse reaction). 2) Increase pressure- increases percentage yield but is expensive to maintain and dangerous to control. 3) Adding CO2, the system tries to counter the increase in reactants so makes the yield faster

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Reply 39

mikyyyyy

for the last six marker i put
2 types of hardness
permanent and non permanent
washing soda removes hardness
allows the sodium to dissolve in the water getting rid of hardness
calcium reacts with the hydrogen reacting to reduce hardness
limestone is used aswell
how many marks?

OCR GATEWAY CHEMISTRY B 16th June C4 C5 C6

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