acids, bases and buffers ( incldues important partial neutralisation calculation)

Question 1

partial neutralisation ( acid and bases chapter question )

Answer 1

notice how all the alkali has reacted ,but there is still some acid left? This is why its called partial neutralisation!

1. DRAW OUT THE WHOLE EQUATION
2. WRITE OUT THE MOLES AT THE START, CHANGE IN MOLES, AND FINAL MOLES…
3. WORK OUT CONCENTRATEION BY MOL/ TOTAL VOLUME ( add volume of acid and conjugate base together)

Question 2

NOTE

Answer 2

ALWAYS, WRITE EQUATION OUT

get starting moles

get change in moles

then get final moles

and then work out whatever is needed

Question 3

Another note ( interms of chemicals having same volume in buffers)

Answer 3

you could enter moles of acid and salt straight into equation as they both have the same new final volume

Question 4

carbonic acid disassociatiokn

Answer 4

h2co3—> H+ (+) HCO3-

Question 5

format for answering acid base equillibrum questions

Answer 5

.state whetehr h+ or oh increases

.state which ions react with what ( EG h+ ions react with conjugate base HCO3)

.state eq movement

eg : equillibrium positions shifts to the left, removing most of the H + ions

Question 6

titration curve of adding acid to base

Answer 6

same as base to acid, but upside down !!!!!!

Question 7

sensetivity of the end point of an indicator

Question 8

water acting as an acid and base

Answer 8

h2o + h2o —> h3o + + oh-

Question 9

phases of the ph curve

Answer 9

1. ph increases slowly a basic solution is added
2. vertical section; ph increases rapidly on addition of small volume of abase as acid and base concentratiosn are very similar (acid is used up more quickly )
3. equivalence point; centre of vertical section of ph titration curve (volume of one solution exactly reacts w volume of the other soltion, amountsu sed match stochiometry of reaction )
4. excess base; ph increase slowly as basic soluition added