Group 2 Reactions - Observations oxygen, water and dilute acids

Question 1

beryllium reaction observations
oxygen

water

dilute HCl

dilute H2SO4 sulfuric acid

Answer 1

beryllium reaction with oxygen - reluctant to burn, white flame

Beryllium no reaction with water

beryllium reaction with dilute HCl rapid reaction

beryllium reaction with dilute H2SO4 sulfuric acid is rapid

Question 2

magnesium reaction observations
oxygen

water

dilute HCl

dilute H2SO4 sulfuric acid

Answer 2

magnesium reaction with oxygen burns easily light white flame

Magnesium has a vigorous reaction with steam but no reaction with water and cold water

dilute hcl reacts vigorously

H2SO4 reacts vigorously

Question 3

Calcium reaction observations
oxygen

water

dilute HCl

dilute H2SO4 sulfuric acid

Answer 3

oxygen Difficult to ignite red flame

water Vigorous reaction with steam no reaction with water

dilute HCl Reacts moderately a hydroxide is formed

dilute H2SO4 Reaction slowed down by the formation of sparingly soluble sulfate layer that covers metal stopping hydrogen bubbles from arising

Question 4

strontium reaction observations
oxygen

water

dilute HCl

dilute H2SO4 sulfuric acid

Answer 4

oxygen difficult to ignite red flame

water reacts rapidly hydroxide formed

dilute HCl reacts vigorously

dilute H2SO4 Reaction is quickly stopped by the formation of and insoluble sulphate layer on the metal surface

Question 5

Reactions with water and oxygen
The reaction of group 2 metals with oxygen follows the following general equation:

Remember than Sr and Ba also form….

Answer 5

2M (s) + O2 (g) → 2MO (s)

Where M is any metal in group 2

peroxide Sr(s)+O2(g)~ SrO2

Question 6

when does Sr and Ba form peroxides

Answer 6

Strontium and barium will also react with oxygen to form strontium or barium peroxide.

Strontium forms this if it is heated in oxygen under high pressures,

but barium forms barium peroxide just on normal heating in oxygen

Question 7

Magnesium reacts extremely ………..with cold water:

chemical formula

and describe the hydroxide

Answer 7

slowly

Mg (s) + 2H2O (l) → Mg(OH)2 (aq) + H2 (g)

is weakly alkaline (pH 9-10) as magnesium hydroxide is only slightly soluble

Question 8

However, when magnesium is heated in steam, it reacts …………with steam to make ………….

Answer 8

vigorously

magnesium oxide and hydrogen gas:
Mg (s) + H2O (g) → MgO (s) + H2 (g)