C9 - Water, pollution and energy

Question 1

What ides hard water make?

Answer 1

Scum and scale, dissolved calcium ions and magnesium ions react with soap to make scum which is insoluble

Question 2

When does hard water make scale?

Answer 2

When heated makes valium carbonate, thermal insulator

Question 3

What is hardness caused by?

Answer 3

calcium and magnesium ions when rain dissolves on compounds such as magnesium sulfate and calcium sulfate

Question 4

What are the types of hardness?

Answer 4

Temporary and permanent

Question 5

Temporary hardness

Answer 5

hydrogencarbonate ion in Ca(HCO3)2

removed by boiling, hydrogen carbonate decomposes to form calcium carbonate which is insoluble

Question 6

Permanent hardness

Answer 6

Dissolved calcium sulfate

Question 7

How can both types of hardness be softened?

Answer 7

Washing soda, sodium carbonate, to it

carbonate react with mg and ca to make insoluble precipitate

Question 8

How can both types of hardness be removed?

Answer 8

running water through ion exchange columns

they have sodium ions and exchange them for calcium or magnesium ions

Question 9

hydrogen and oxygen

Answer 9

water

exothermic

Question 10

hydrogen-oxygen fuel cells

Answer 10

electrolyte is a solution of potassium hydroxide and the electrons are porous carbon with a catalyst
hydrogen anode
oxygen cathode
H loses electrons