Measuring Amounts (Moles & Volume of Gas)

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Created by: Jodie Randell
Created on: 16-04-11 16:18

Measuring Amounts (Moles)

Knowing the number of moles of something is important to see how much raw material you need for a reaction

1 Mole is the same as the atomic mass of an element

Mass= Mr x Moles

Q. How many moles are there in 66g of CO2 (C=12, 0=16)

1)Rearrange formula Moles= mass/mr

2)Put numbers into formula 66/44 = 1.5 moles

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Measuring amounts (Volume of gas)

One mole of any gas occupies 24 dm3

Volume of gas = (Mass/Mr) x 24

So Volume = Moles x 24

Q. Find the volume of carbon dioxide produced (at room T and P) when 2.7g of carbon is completely burned oxygen. (C=12, O=16)

1) Write out the equation C + O2 --> CO2

2) Find the amount of moles for Carbon m=mass/mr 2.7/12 = 0.225

3) Ratio of C:CO2 is 1:1 so mole number is the same. So you put 0.225 into the equation 0.225 x 24 = 5.4dm3

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Comments

Willow Woodward

Report Fri 21st September, 2012 @ 21:20

in measuring amounts (volume of gas), why is the ratio of C:CO2 1:1.. thats the only bit i don't understand

Jodie Randell

Report Sun 27th January, 2013 @ 16:53

Because the number of moles of carbon and carbon dioxide is the same. It the equation would of been 2C + O2 ---> CO2 + C- Then the ratio between carbon and carbon dioxide would be 2:1 as there is 2 x as many moles in 2C than there is in the CO2.