Chapter 4

Question 1

What is the difference between strong and weak acids ?

Answer 1

Strong acids fully dissociate in solution
Weak acids only partially discoatiate in solution

Same concepts applies for bases

Question 2

What is the reaction between metals and acids ?

Answer 2

Metal + acid -> salt + hydrogen

Question 3

How to make a standard solution ?

Answer 3

1. Weigh out a precise amount of solid correct to 2 d.p
2. Add to a small volume of distilled water in beaker
3. Stir with a glass rod thoroughly until dissolved
4. Transfer to a volumetric flask, and rinse beaker with distilled water
5. Fill volumetric flask with distilled water, until bottom of meniscus is on scratch line
6. Add stopper and mix, moving up and down

Question 4

How to perform a titration ?

Answer 4

• measuring 25cm^3 of 1 one of the solutions with a volumetric pipette and placing into conical flask
• other solution is placed in burette filled to 0 line
• add a few drops of single indicator to the conical flask with
• tap is opened on burette into the conical flask until indicator changes colour
• as the end point is reached the flow of the burette should be slowed to drop wise
• multiple titres taken until concordant results

Question 5

What are percentage uncertainties ?

Answer 5

Percentage uncertainty = uncertainty/ measured value x 100

When you are adding or subtracting 2 measurements together then you add the uncertainties

Question 6

What is the oxidation state ?

Answer 6

The oxidation state of an atom is the charge that would exist on an individual atom if the bonding were completely ionic

Question 7

What are the rules for oxidation states?

Answer 7