unit 3 Flashcards
(19 cards)
Why is lithium a stronger reducing agent than the next element in group one in water, when the trend is stronger as you go down in group one
Lithium is such a dense centre of positive charge because it is so small. So when it becomes a + ion it attracts lots of water and its hydration energy is huge. So lithium is only stronger reducing when in water, when it isn’t in water it is weaker
What do group one form with oxygen ?
Ionic oxides
Group one with water?
Explosive produce metal hydroxide and hydrogen gas. They make strong alkali solutions
Properties of group one hydroxides
strong alkali
ionic solid -soluble
Solubility of group one halides?
All soluble because hydration energy overcomes lattice energy
What do group one nitrates turn into when heated?
Turn into nitrite other metals just give off nitrogen dioxide
Properties of group one hydrides?
ionic Hydrogen acts as the - making them really reactive.
eg LiAlH4 is very good reducing agent can reduce acids aldehydes and ketones to alcohols
Group 1 hydrides act as what?
Reducing agents
What is hydrogen bonding?
Electrostatic attraction between lone pair and delta positive hydrogen
What is a reducing agent?
One which gets oxidised itself. It donates an electron
What bonding occurs in HF?
Covalent
Why do boiling points of group 16 hydrides not follow the trends you would expect compared to grou 14 hydrides
Hydrides of oxygen can hydrogen bond to each other- there is no hydrogen bonding in group 14
Which properties of group 1 metals increase down a group?
Reactivity with water and atomic size
Group 1 hydroxides all exist as ionic solids, true or false?
True
All group 1 hydrides are very soluble? true or false
false, all are very soluble with the exception of lithium which needs heating
Why does lithium have a higher redox potential (against the trend)
It has such a large hydration enthalpy that is therefore forms a hydrated ion easier
What is the most common way of manufacturing hydrogen gas
reacting hydrocarbons with steam
Which compound is responsible for causing hardness in water?
Calcium hydrogencarbonate
In the water softening process an ion echange column is used to replace ca2+ with na+ true or false
True
