Physical Chemistry

Question 1

How does methyl orange react to acid and alkalines ?

Answer 1

yellow in alkaline solutions

Red in acidic solutions

Question 2

How does phenolphthalein react to acids and alkalines ?

Answer 2

Bright pink in alkaline

Colourless in acidic

Question 3

define an acid ?

Answer 3

A source of hydrogen ions

Question 4

Define and alkali ?

Answer 4

A source of OH- ions (hydroxide )

Question 5

How do metals react depending on their position in the reactivity series ?

Answer 5

• metals below hydrogen dont react

- metals above react to produce hydrogen and a salt

Question 6

What happens when metal oxides react with acids ?

Answer 6

Metal oxide + acid —-> salt + water

Question 7

How does litmus react to acid and alkaline substances ?

Answer 7

Its turns blue in alkaline
Red in acidic
Pink in neutral

Question 8

Metal hydroxide + acid —>

Answer 8

Salt and water

Question 9

Metal carbonate + acid —>

Answer 9

Salt + carbon dioxide + water

Question 10

What are the solubility rules

Answer 10

i)all common sodium , potassium and ammonium salts are soluble
ii)all nitrates are soluble
iii) common chloride are soluble except silver chloride
iv)common sulphates are soluble apart from barium and calcium
V) come on carbonates are soluble except those of sodium, potassium and ammonium

Question 11

How do you get a soluble salt from an acid

Answer 11

The Excess base/ method

1) the required volume of acid is measured out in a beaker with the measuring cylinder the metal or base is weighed out and the solid added in small portions to the acid in the beaker
2) when no more solid is our dissolving and all of the acid has been neutralised there should still be a little bit of solid leftover
3) filter out the solid using a filter funnel and filterpaper
4) leave the solution to cool in crystallise so that you can have crystals of the Salt you need

Question 12

What is acid alkali titration

Answer 12

1) a known volume of acid is put in a conical flask with indicator added
2) The alkali is added slowly using a burette until the indicator turns pH 7 and all of the acid has been neutralised
3) The volume needed for neutralisation is then noted and they repeat the steps but with out the indicator contaminating the solution
4) The solution is then transferred into evaporating dish in which the water is lost and crystallisation takes place

Question 13

What is a precipitation reaction

Answer 13

A reaction which involves two soluble solutions reacting to make an insoluble salt

Question 14

What are the factors that affect the rate of a reaction

Answer 14

The surface area , the concentration of the solution,the pressure of gases the temperature and the use of a catalyst

Question 15

How to surface area affect the rate of reaction

Answer 15

The larger the surface area The more room there is for the particles to collide therefore the more frequent collisions are.the faster the reaction

Question 16

How does The increase in concentration affect the speed of the reaction

Answer 16

There are more particles in the set volume therefore the particles are going to collide more frequently

Question 17

How does temperature affect the rate of reaction

Answer 17

The particles have more energy therefore are more likely to collide successfully in addition they are have more energy so they are going to collide more frequently as they are moving around more

Question 18

How does a catalyst affect the rate of reaction

Answer 18

It provides an alternate route for the particles involving a lower activatiom energy

Question 19

Describe the decomposition of hydrogen peroxide

Answer 19

2H(2)O —-> 2H(2)O +O(2)

Question 20

What is used to catalyse the decomposition of hydrogen peroxide

Answer 20

Manganese oxide

Question 21

What is activation energy

Answer 21

Activation energy is the minimum energy required for a reaction to start