Group 2 reactions Flashcards
What is the equation for when group 2 metals react with oxygen?
2M(s) + O2(g) -> 2MO(s)
What is the equation for when group 2 metals react with water?
M(s) + H2O(l) -> M(OH)2(aq) + H2(g)
Why are the reactions between group 2 and acids not acid-base reactions?
It is a transfer of electrons, not protons
How does magnesium react with water?
It doesn’t react with cold water but Mg(OH)2 is produced when reacted with steam
How does calcium react with water?
It reacts with water to produce Ca(OH)2 which partially stays solid but some also dissolves to produce an alkaline solution
What is the trend in group 2 reactivity?
It increases down the group
What is the other trends increase down the group?
Reactivity of elements with water, solubility of metal hydroxide and pH of metal hydroxide
What would you see when a group 2 metal reacts with water?
Grey solid dissolves in colourless solutions, colourless gas produced and effervescence occurs
What are the uses of group 2 oxides and hydroxides?
It reacts with acid to form salt and water, antacids e.g. Mg(OH)2 - milk of magnesia and added to soil to increase pH e.g. CaO or Ca(OH)2
What is solubility?
A measure of the ability of a solute to dissolve in a solvent (moldm-3)
What is an alkali?
A type of base that dissolves in water, forming hydroxide ions
What is an alkaline?
A term used to describe a solution containing hydroxide ions
What is alkalinity?
A measure of the concentration of hydroxide ions present in an alkaline solution
What is pH?
A measure of the concentration of hydrogen ions present in a solution
