General Flashcards
What is the molecular formula?
The actual number of each atom in a molecule.
State the relative mass of a proton, neutron and electron.
- Proton - 1
- Neutron - 1
- Electron - 0.0005
How do impurities affect melting points and boiling points?
- Melting points decrease
2. Boiling points increase
What is the empirical formula?
The simplest ratio of atoms in a molecule.
What are isotopes?
Atoms of the same element that have different numbers of neutrons.
As molecular mass increases, what happens to the rate of diffusion?
It decreases.
What is diffusion?
The spreading out and intermingling of liquids and gases caused by the random movement of particles.
State the equation to calculate the number of moles.
Mass / Mr
What is avagadro’s number?
6.02 x 10^23
State the main property of noble gases.
They are very unreactive.
State a use of noble gases and give an example.
To provide an inert atmosphere
E.g. Helium in balloons
Argon in lamps
What are the products of complete combustion?
Carbon dioxide, water and lots of energy
State the equation for the volume of a gas (in dm^3) at rtp.
Number of moles x 24
What are radioisotopes used for? (3)
- Cancer treatment (cobalt 60)
- To check for leaks (tracers)
- Carbon dating
What do most nitrates thermally decompose into?
A metal oxide, oxygen and nitrogen dioxide
What do potassium and sodium nitrates thermally decompose into?
A metal nitrite and oxygyen
How does the thermal decomposition of nitrates change as you go down the group?
It increases.
What do most hydroxides thermally decompose into?
Metal oxide and water
What do potassium and sodium hydroxides thermally decompose into?
They do not decompose.
What do most carbonates decompose into?
Metal oxide and carbon dioxide.
What do potassium and sodium carbonates thermally decompose into?
They do not.
