Chapter 4 - Chemical Changes

Question 1

What is the pH scale

Answer 1

PH scale is a measure of how acidic or alkaline a solution is

It goes from 0 to 14

Question 2

What happens the lower or higher you go down the pH scale

Answer 2

The lower the pH of the solution the more acidic it is

The higher pH of the solution the more alkaline it is

Question 3

What colour on the pH scale are acids and what colour are alkalis

Answer 3

Acids = red
Alkalis = blue/purple

Question 4

Can you measure the pH of the solution

Answer 4

You can measure the pH of the solution using an indicator which is a dial that changes colour depending on whether it’s above or below a certain pH

You could also use the pH probe attached to a pH meter which will measure the pH electronically

Question 5

What is a base

Answer 5

A base is a substance with a pH greater than seven

Question 6

What happens the acids in water

Answer 6

Acids ionise in aqueous solution which means they produce hydrogen irons, H +

Question 7

What is a PH

Answer 7

The pH of an acid or alkali is a measure of the concentration of H+ ions in the solution

Question 8

What does the concentration of H plus irons irons increase by for every decrease of one on the pH scale

Answer 8

The concentration of H+ irons increases by a factor of 10

Question 9

What do all metal oxides and metal hydroxide is form when they react with acid

Answer 9

Salt and water