URGENT A level question
2 (a) Fig. 6.1
(b) A gas cylinder of internal volume 0.050 m3 contains compressed air at 21 °C and pressure
1.2 × 107 Pa. The molar mass of air is 0.029 kg mol–1.
(i) Calculate
1 the number of moles of air in the cylinder
number of moles = ........................250......................
2 the mass of air in the cylinder.
mass = .......................7.1......................... kg
[3]
(ii) An additional 1.5 m3 of air at 21 °C and at atmospheric pressure, 1.0 × 105 Pa, is pumped
into the cylinder. Calculate the new pressure of air in the cylinder, assuming no change in
temperature during the process.
pressure = ...................??.......................... Pa [4]
For the last part of the question, why does the mark scheme say not to include the added 1.5m^3 of volume in the calculation ie to say that P = nRT/V, where n is the moles before + new moles?
(b) A gas cylinder of internal volume 0.050 m3 contains compressed air at 21 °C and pressure
1.2 × 107 Pa. The molar mass of air is 0.029 kg mol–1.
(i) Calculate
1 the number of moles of air in the cylinder
number of moles = ........................250......................
2 the mass of air in the cylinder.
mass = .......................7.1......................... kg
[3]
(ii) An additional 1.5 m3 of air at 21 °C and at atmospheric pressure, 1.0 × 105 Pa, is pumped
into the cylinder. Calculate the new pressure of air in the cylinder, assuming no change in
temperature during the process.
pressure = ...................??.......................... Pa [4]
For the last part of the question, why does the mark scheme say not to include the added 1.5m^3 of volume in the calculation ie to say that P = nRT/V, where n is the moles before + new moles?
The second lot of air is at a lower pressure, in order to pump it into the cylinder containing the original air it'll need to be compressed to a higher pressure (and therefore lower volume)
You'll need to work with the mass or number of moles of the second lot of air which are going to remain constant as the second lot of air is compressed.
You'll need to work with the mass or number of moles of the second lot of air which are going to remain constant as the second lot of air is compressed.
Reply 3
I see, i get that the dimensions of the cylinder are constant and therefore so is the volume. So does this mean the question is kind of poorly worded as all its saying is that there is additional gas instead of increase in volume?
(edited 11 months ago)
Original post by efsfsf\\eeeeeee
I see, i get that the dimensions of the cylinder are constant and therefore so is the volume. So does this mean the question is kind of poorly worded as all its saying is that there is additional gas instead of increase in volume?
i guess so. But it does say whats the pressure of the cylinder, suggewsting that you use the volume of the cylinder. i see how it might be confusing
Quick Reply
Related discussions
- UCL UPC Interview
- URGENT! I didn't write my answer number in the margin
- Warwick IFP in Finance - interview
- Can I study Pharmacy without math A-Level???
- Politics A-level
- URGENT PLEASE A level physics help
- Level 2 Diploma in Business Administration - Unit 4 HELP
- UK school choice
- How were the 2024 OCR A AS level Chemistry Papers?
- Urgent
- University of Sheffield Current Language & Education Student - Ask Me Anything
- clearing URGENT URGENT URGENT URGENT URGENT
- Maths paper 3 a level AQA
- urgent question
- Level 3 health and social care
- Revision Mindset
- A Level Subjects
- URGENT A Level Maths A*
- Question URGENT
- GCSEs help urgent
Latest
Trending
Last reply 2 months ago
A level Edexcel physics aluminium foil passing through a uniform fieldLast reply 3 months ago
If you could spin a hand spinner at the speed of light could it affect Space Time?Last reply 3 months ago
Using the equatorial diameter, how large is Mercury compared to Earth?Last reply 3 months ago
very urgent qs for someone that got 9 in gcse physics edexcel
