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# hey, any1 wanna help me with my chemistry cw?! watch

1. heya, im doing my chem cw on rates of reaction...basically im a bit confused cuz i did it months ago and now what i wrote doesnt make any sence...
ok, i have some of my results, for using 0.10m, 0.20m, 0.30m, 0.40m and 0.50m of acid etc up to 1.0m and they all show that how long it takes for the reaction to produce how ever much gas, when the reaction ends 50cm3 of gas was collected

but i was looking at my one for 0.10m of acid and it ends at like 26 something cm3's of gas, should they all profuce the same amount of gas? i'd be sooo greatful if sum1 could help im so stuck with this!

sorry for the boringness of this! xx
2. At 0.10 the reaction would be reall slow, so you probably didn't leave it long enough for all the gas to be collected. It is a rule that the amount of products should equal the amount of reactants, and so there should be the same amount of gas given off for every one - the only varibale should be the concentration of the acid and the time it takes for 50cm3 of gas to be given off.

When you draw the graph you can then find the gradient and then the rate of reaction in cm3/s or ml/s.

I suspect you didn't leave it long enough for all the gas to be given off - something to talk about in your evaluation (if you do, and explain why there is the mistake, you'll get really good marks for your evaluation).
3. (Original post by Juxtapiped)
At 0.10 the reaction would be reall slow, so you probably didn't leave it long enough for all the gas to be collected. It is a rule that the amount of products should equal the amount of reactants, and so there should be the same amount of gas given off for every one - the only varibale should be the concentration of the acid and the time it takes for 50cm3 of gas to be given off.

When you draw the graph you can then find the gradient and then the rate of reaction in cm3/s or ml/s.

I suspect you didn't leave it long enough for all the gas to be given off - something to talk about in your evaluation (if you do, and explain why there is the mistake, you'll get really good marks for your evaluation).
aww i love u thanks you so much except now im a bit confused cuz i did it on a computer programme, but at least i know it's meant to be 50cm3! so i probably just messed up somewhere along the line

thanks ever so much

have a gd day
4. No problem - I remember the days of god damn Science coursework. I'll give you some tips on how to get top marks, they worked for me!

They mark it in 4 areas:

1) Planning and Prediction (out of 8)

2) Results (out of 8)

3) Analysis (out of 8)

4) Evaluation (out of 6)

Planning

Make it VERY detailed, and don't forget a diagram. Back up everything you say with some scientific fact - and in the prediction use science constantly.

Results

Make the table of results clear, and don't forget units and measurements (they are really important) I got marked down once for doing to the nearest decimal point when it should have been to the nearest 2! Graphs should always be labelled everywhere with measurements etc.

Analysis

Combine MATHS and SCIENCE - to get the good grades use maths and formulas and stuff - and USE SCIENCE everywhere.

Evaluation

Recognise faults in the experiment and give the reason for it USING SCIENCE etc.

They are the sections to work on - Good luck!
5. that last bit really helped, thanks so much!

i'll probably be on here again tomorrow with all the little bits that always confuse me! uve been really helpful
6. (Original post by Unregistered)
that last bit really helped, thanks so much!

i'll probably be on here again tomorrow with all the little bits that always confuse me! uve been really helpful

Happy to help!
7. Im doing the same thing. Ive got the amounts of gas given off but I dont know what sums to do to find out the concentrations. any help?

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Updated: February 15, 2004
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