Removing Hardness

Question 1

Heating softens … Hard water as the …ions and …ions firm ….. Which is removed

Answer 1

Temporary

Calcium and magnesium ions

Form scale

Question 2

Why is heating not viable on a large scale (3)

Answer 2

Uses lots of energy

Expensive

Doesn’t remove permanent hard water

Question 3

… Hardness can be removed by reacting with … Forming …. Which is removed

Answer 3

Temporary hardness

Reacting with soap

Scum is Formed

Question 4

Washing soda removed …. Hardness

Answer 4

Temporary

Question 5

The …. In washing soda reacts with ….. And …. Ions to form solid ….. And …. Which is removed

Answer 5

Sodium carbonate in washing soda

Reacts with calcium and magnesium ions

Forming solid calcium carbonate and magnesium carbonate

Question 6

Using washing soda is

Answer 6

Quick and cheap

Question 7

Equation for softening water by heating

Answer 7

Hydrogen carbonate ions decompose to carbonate ions +water+ carbon dioxide

Question 8

Water softening by heating symbol equation

Answer 8

2HCO3-> CO3+ H2O + CO2

Question 9

Temporary hard water contains what 2 substances

Answer 9

Calcium hydrogen carbonate

Magnesium hydrogen carbonate

Question 10

Soap with only lather when

Answer 10

All the dissolved calcium hydrogen carbonate has reacte and Formed calcium stearate

Question 11

Chemical name for scum

Answer 11

Calcium stearate