Particles and formulae Flashcards
Why does it take a long time to diffuse why not straight away?
It doesn’t diffuse straight away because the molecules keep bumping into each other and slowing the process down. They are knocked back and forth. The diffusion happens faster if the gases are hot because the molecules are quicker having more energy.
Explain the experiment of air and chlorine diffusion in detail when the glass slip is removed between both substances.
After 5 minutes the particles from the chlorine have slowly moved upwards slowly diffusing with the air; the chlorine particles are mixing with the chlorine particles. The chlorine continues to spread upwards. After half and hour the chlorine gas has completely diffused with the air particles and has spread through the air evenly. The entire jar is full of chlorine and air in a uniform mixture.
What difference do you think you would notice if the gases had been heated before the experiment?
If the gases had been heated before the experiment it would have been a much quicker experiment, because the gas particles would be randomly moving around rapidly. It would speed up the process due to the particles having more energy.
Explain heating curves and cooling curves layout in terms of particles
To start with the heat makes the particles in the solid vibrate more vigorously. The temperature of the solid increases. During the melting the temperature stays the same as the energy is now used to overcome forces so the particles move freely. The liquid then gets hotter. During the boiling the temperature stays the same again asd the energy is now used to break forces so particles escape into a gas state.
Explain why the graph has the shape it does during the change of state in a cooling curve.
As the liquid changes to solid the particles give out energy which makes up for the cooling so the temperature remains the same.
What is formed when iodine crystals are heated?
The iodine sublimes producing a purple gas.
What is meant by distillation?
To obtain a pure liquid from a solution. The method is evaporation followed by condensation.
What is a compound?
When two or more different element are chemically bonded to each other.
What is a mixture?
When two or more elements are mixed together, not chemically bonded.
What’s the formula for a carbonate and the valency hooks?
CO3 with valency 2
Valency and formula for nitrate
NO3 with valency 1
Formula and valency for a hydroxide
OH with valency of 1
Valency and formula of a sulphate
SO4 with Valency 2
Sodium&chlorine gives you
Sodium chloride
Aluminium&bromine gives you
Aluminium bromide
