Lecture 16 (Group 2 Elements, etc.)

Question 1

What agent would an element with a high standard reduction potential be?

Answer 1

strong reducing agent

Question 2

Are M2+ ions good lewis acids or bases?

Answer 2

Lewis acid

Question 3

What is passivation?

Answer 3

upon air exposure, the metals are covered by a layer of oxide that protects them from further reaction with air or moisture

Question 4

How are Be, Ca, Sr, and Ba prepared?

Answer 4

electrolysis of molten MCl2 salts

Question 5

How are Sr, and Ba prepared using reduction?

Answer 5

reduction of SrO, BaO with Al.

Question 6

What reacts most with non-metals?

Answer 6

strong reducing agents

Question 7

What is coordinative (or dative) bonds?

Answer 7

covalent bonds where the bonding electrons come from only one of the bonding atoms

Question 8

What group 2 hydroxide is amphoteric?

Answer 8

Be(OH)2

Question 9

What does amphoteric mean?

Answer 9

compound reacts with acids and bases

Question 10

What is water hardness?

Answer 10

The content of Mg2+ and Ca2+ in water

Question 11

How can temporary hardness be overcome?

Answer 11

By boiling

Question 12

What type of hardness cannot be overcome by boiling?

Answer 12

permanent hardness

Question 12

What type of hardness cannot be overcome by boiling?

Answer 12

permanent hardness

Question 13

What is the hardness of Calgary drinking water?

Answer 13

141-250mg/L CaCO3

Question 14

What are the problems of water hardness?

Answer 14

1) Formation of limescale when heating and evaporation

2) Formation of soap scum instead of lather

Question 15

What is water softening?

Answer 15

The boiling (if temporary) or distillation (if permanent) of water

Question 16

What is chelation?

Answer 16

The formation of tow or more separate bonds between a bidentate (or polydentate) ligand and a central atom

Question 17

What do chelating agents do to metal ions?

Answer 17

Sequester the metal ions into a soluble form