5.1 Moles 2
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What is volume of gas measured in?
cubic metres
What is volume of gas measured in for mole calulations?
cubic decimetres
What is the scale factor between cm cubed and dm cubed?
1000
cubic centimetres -> cubic decimetres
divide by 1000
cubic decimetres -> cubic centimetres
multiply by 1000
Equation for moles of a gas?
moles = volume / 24 cubic decimetres
State the equation linking moles, volume and concentration
moles = concentration x volume
What is the concentration of a solution a measure of?
how much solute dissolved per unit volume
What is the equation for concentration of a solution?
concentration = moles / volume
What is titration used for?
neutralise a particular volume (acid/alkali)
Name the two special pieces of equipment for titration
volumetric pipette burette
What is the volumetric pipette for?
measuring 25cm cubed accurately
What is the burette for?
measuring a volume to the nearest 0.05 cm cubed
Why is universal indicator not used in titration?
colour change is not sharp/defined
Which indicator should be used in titration?
phenolphthalein/methyl orange
Why is a pipette not suitable for adding acid/alkali to complete neutralisation?
pipette only measures on volume - 25 cm cubed
What are concordat results?
differ from each other by 0.2 cm cubed or less
What is the first step of set up for titration?
use volumetric pipette 25 cm cubed of unknown into conical flask
Where does the 25 cubic cm of unknown go in step 1?
conical flask
What is added to the conical flask in step 2?
indicator
What is the burette filled with in step 3 of set up?
known solution
Where should the burette of known solution be clamped?
above the conical flask
In step 1 of usage, what should the volume of known be measured to?
nearest 0.05 cubic cm
What is the role of the burette in step 2 of usage?
add known solution to conical flask