`Outcome 1- Water/ Ionic equations Flashcards Preview

Unit 2 Chem > `Outcome 1- Water/ Ionic equations > Flashcards

Flashcards in `Outcome 1- Water/ Ionic equations Deck (25):

Properties of water

-High melting and boiling points of water compared wit h similarly sized molecular substances.
-Expands when frozen
-Relatively high latent heat value for fusion and evaporation
-High specific heat capacity
-Ability to dissolve other substances


Explain how the properties of water can be explained by the nature of the intermolecular forces between water molecules

The existence of hydrogen bonding between water molecules allows it be a good solvent for other polar substances as well as many ionic substances


Why is water different from most liquids with respect to its density in the solid and liqud states

Its solid form is less dense than its liquid form. The molecules are arranged in a more structured hexagonal way. This means ice floats on water and that water freezes from the surface down.


What is latent heat

Measures the amount of energy required to change the state of a given amount of substance


What is specific heat capacity

The amount of energy needed to raise the temperture of one gram of the substance by one degree celcius.


How is water unique to latent heat and SHC

it has the ability to absorb large amounts of heat energy with only a minimal increase in temperture. The higher the SHC is the more energy it must absorb to raise its temp


Why would life not exist if ice was denser than water

If Ice were denser than water, bodies of water would freeze solid during winter and the aquatic life would die.


How does "like dissolves like" explain that- Potassium chloride dissolves in water

Potassium chloride is ionic and water is Polar


How does "like dissolves like" explain that- Ammonia dissolves in water

Ammonia and water are both polar


How does "like dissolves like" explain that- Methane is insoluble in water

Methane is non polar where as water is polar


Latent heat of fusion

The change from solid to liquid


Latent heat of vaporisation

The change from liquid to gaseous


Symbol for latent heat is

l and units are kjmol-1 and jkg-1


Latent heat of fusion of water is

6.02kj mol-1


How much energy is needed to raise 250ml of water from 20C to 100C?

250x 4.18x (100-20)
=83 kj or 8300j or 4.2x 10^3 j


Specific heat capacity of water



Is water electrically neutral?

Pure does conduct electricity very slightly, however the amount is so tiny, it is still viewed as a non conductor.
Water molecules can react with each other. this is called SELF IONISATION OF WATER



They are polar compounds so they are strong enough to break the cohesive hydrogen bonds. This dissolves with the water


Hyrdro phobic

Cannot overcome the cohesive nature of water.
These molecules are non polar and cannot dissolve


Capillary action

When water molecules are molecules are attracted to other water molecules by cohesion (Attraction of water) This causes water molecule to go up a glass straw


Using water a solvent

Industrial Applications
Biological Applications
Domestic Applications


Two reactions when mixing solutions

Nuetralisation and precipation


Dissociation is

Ionic compounds dissolving in water


Ionisation is

Covelant compounds dissolving in water


Equation for self ionisation of water

H2O + H2O -> H3O+ + OH-