Current Year 12 Thread Mark I (2012-2013)

Indeed! wouldn't change my college for anything though

Okay, biology test was decent today. As usual, the topics I concentrate more on while revising doesn't come up. *sigh*
Tomorrow, I'm doomed. My two weakest subjects, chemistry and physics. The formulas are just confusing me recently. I just don't know when to use where.

Hi everyone!

Same. As I am pm'ing someone who goes to another grammar school around my area aswell, I think going to this sixth form was the best decision.

I wouldn't change the past 2 years I've had there for anything. I will miss it so much next year

Looking forward to the next 2 year's

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Thank you they just seem so bad compared to the rest of TSR

last year at college and 1st year at uni?

I'm sure many people on TSR are honest about their grades but you can't be sure

Hi how you doing?


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Spending the next 2 year's here and yeah, hopefully if I get a place to study medicine at Notts (unlikely)

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What don't you get about chemical equations? Can't help with physics though.

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Argh. I have no idea if I have physics homework in for tomorrow or not, and the college email is down. Caroline is going to have my head off if I miss another one..

Here's a question we did earlier today where I got confused if you don't mind.

a.) Petrol is basically octane (C8H18).
An average small car travels 10 000 miles a year. The fuel consumption is 7.5 miles per litre of petrol. 1 litre of petrol has a mass of 1000g.
What volume and mass of CO2 does this car produce in a year?

Anyway, mole ratio is 1:8

If you don't mind, could you explain the steps? We did it this morning so I know you have to convert stuff to moles but I don't understand why or how.


And if anyone can help me with Physics. I'm a little bit confused as to how I'm supposed to calculate the displacement. It's basically distance, right? So would it just be v*t? Apparently I have to calculate the area of the triangle on the graph, not sure if this is right.

Sorry for asking for so much

First, work out how many grams of octane is produced in a year. This should be fairly straightforward from the information that you have been given (i.e. fuel consumption is 7.5 miles per 1 litre, the car travels 1000 miles etc.).

After doing that, you should have the mass of the octane produced in a year. Use Moles = Mass/Mr to work out the number of moles of octane that are produced. Then multiply this by whatever the mole ratio for CO2 is to get the number of moles of CO2.
Once you've done that, use the formula Moles = Mass/Mr to to find the mass of CO2 produced.

For the second one, remember the equation:

Moles = Volume (in dm^3)/24

For the physics question, I presume you are looking at a speed time graph? If so then yes, you have to calculate the area under the graph to find the displacement.

That makes so much more sense to me now! Thank you so much! I was really lost this morning and didn't want to ask since everyone knew what they were doing. Thank you for confirming the physics problem too.

You're the best!
You guys are awesome.

Here's a question we did earlier today where I got confused if you don't mind.

a.) Petrol is basically octane (C8H18).
An average small car travels 10 000 miles a year. The fuel consumption is 7.5 miles per litre of petrol. 1 litre of petrol has a mass of 1000g.
What volume and mass of CO2 does this car produce in a year?

Anyway, mole ratio is 1:8

If you don't mind, could you explain the steps? We did it this morning so I know you have to convert stuff to moles but I don't understand why or how.


And if anyone can help me with Physics. I'm a little bit confused as to how I'm supposed to calculate the displacement. It's basically distance, right? So would it just be v*t? Apparently I have to calculate the area of the triangle on the graph, not sure if this is right.

Sorry for asking for so much

Gosh!

No problem at all!

If you don't mind checking what I've done for a different question.

- If we have been given 0.24g of Mg. What volume of a 0.01 moldm^-3 of HCl is needed for complete reaction?

So I got... Concentration = 0.01 moldm^-3 Mass = 0.24g Volume = ? Mole ratio = 1:2

I converted the mass of Mg into mols with Mols=Mass/Ar
0.24/24 = 0.01

For mols of HCl I just multiplied the above with mole ratio.
0.01 x 2 = 0.02

I got that far, I'm not sure what to do.

Looks good, now you can use the forumula:

Number of Moles = (Concentration x Volume)/1000 to work out the volume of HCl.