Solubility of group 2 hydroxides and sulphates

  • Created by: Zammi10
  • Created on: 28-02-17 20:14
What happens to the solubility of group 2 hydroxides down the group?
The solubility of group 2 hydroxides increases down the group and the solutions become more alkaline down the group
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What happens to the soluility of group 2 sulphates down the group?
The solubility of group 2 sulphates decreases down the group
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What are some of the uses of hydrated calcium sulhate
white pigment in paints and dues. Used as casts in dentristy
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Barium sulphate?
Can help diagnose intestinal problems as it shows up on an x-ray like bone and metal.
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With barium oxide and barium hydroxide, the usual reactions of a metal oxide and hydroxide with dulute sulphuric acid don't occur in practise. Why not?
Because BaSO4 forms which is insoluble so it forms a thin layer on the metal surface. This stops any more acid form reacting
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What does the thermal stability of group 1 and 2 nitrates and carbonates depend on?
The charge density of the cation
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The larger the charge and smaller the radius...
the larger the charge density and polarising power of the cation on the anion- can polarise the C-O or O-N bond
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Why are group 2 nitrates and carbonates generally less stable than group 1
because they have a greater charge density so can polarise the bond with the anion more.
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thermal stability of group 1 metal carbonates
They are all stable to heat except Lithoum carbonate because it is able to polarise the C-O bond to release carbon dioxide- to form the oxide ion
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thermal stability of gruop 2/
Stability increaes down the group because charge density decreases, less polarisation of C-O bond therefore more heat required to break the bond and release the oxide ion
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MgCO3 -->
MgCO3 --> (heat) MgO + CO2
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Thermal decomposition of group 1 nitrates?
They all decompose with heat
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What do group 1 nitrates generally decompose to?
a metal nitrate and oxygen (bar lithium which reacts like group 2)
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2NaNO2--> heat
2NaNO3 --> 2NaNO2 + O2
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Why do they not react like lithiuim?
They do not have a high enough charge density to polarise the O-N bond
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How do group 2 nitrates decompose?
Produce a metal oxide, NO2 + O2
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2Mg(NO3)2 -->
2MgO + NO2 + O2
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LiNO3 -->
LiO + NO2 + O2
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what happens to thermostability down the group?
they become more thermostable down the group
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Lithium flame colour
crimson
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Na
Yellow
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K
Lilac
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Mg
No colour
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Ca
Brick red
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Sr
Dark red
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Ba
Apple Green
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What is a flame photometer?
It is an instrument that accurately measures the wavelengths of ligth given out by ion susch as Na, K and Ba in a sample by analysing the flame produced.
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Why is a flame photometer used?
to find te levels of Na and K ions in blood samles. To moniitor the cocnetrations of Na, K and Ca ions during the production of wines.
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Card 2

Front

What happens to the soluility of group 2 sulphates down the group?

Back

The solubility of group 2 sulphates decreases down the group

Card 3

Front

What are some of the uses of hydrated calcium sulhate

Back

Preview of the front of card 3

Card 4

Front

Barium sulphate?

Back

Preview of the front of card 4

Card 5

Front

With barium oxide and barium hydroxide, the usual reactions of a metal oxide and hydroxide with dulute sulphuric acid don't occur in practise. Why not?

Back

Preview of the front of card 5
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