CT Rev Flashcards
Recall the colours and physical states of chlorine, bromine and iodine at room temperature.
chlorine is a pale green gas at room temperature , bromine is an orange liquid and iodine is a grey solid.
What are some physical properties of halogens
The halogens have low melting points and low boiling points
Describe the chlorine test
litmus paper is used. The litmus paper must be damp. Litmus paper turns white. When chlorine gas is present, litmus paper will be bleached and turn white.
Describe the reactions of the halogens, chlorine, bromine and iodine, with metals to form metal halides, and use this pattern to predict the reactions of other halogens.
When halogens react with metals, they form salts, also known as halides. The halide ion will have a negative charge and the metal ion will have a positive charge.
Recall that the halogens, chlorine, bromine and iodine, form…
hydrogen halides which dissolve in water to form acidic solutions, and using this pattern you can predict the reactions of other halogens.
Explain the relative reactivity of the halogens in terms of electronic configurations.
Halogens want to gain one electron to form a -1 ion, so that it can have a full outer shell. The easier it is to gain an electron, the more reactive the halogen is.
As you go down group 7, reactivity of the halogens decreases because: The atomic mass of the halogens increases.
Describe different changes that can occur as a reaction proceeds.
The change in mass (due to a gas being given off), volume of gas produced, concentration of acid or the pH of the acid
Suggest different experimental methods to investigate rates of reaction
measurements of mass of reactants against time, volume of gas released against time, concentration of reactant or product against time
Explain why changes in the energy of particles affect rates of reaction.
An increase in energy will increase the movement of particles, which will increase the frequency of collisions
Explain why changes in the frequency of collisions between particles affect the rate of reaction
Reacting particles can form products when they collide with one another provided those collisions have enough kinetic energy and the correct orientation.
Explain why changes in temperature, concentration, surface area and pressure affect the rate of reaction
Temp increases energy
Concentration increases particles
Surface area increases concentration
Pressure increases concentration
Which all increase frequency of reactions
Describe ways of speeding up chemical reactions.
Increase in pressure, concentration, temperature
Describe ways of slowing down chemical reactions.
decrease in pressure, concentration, temperature
Describe what a catalyst does.
Speeds up reactions
Explain how catalysts are useful.
they make reactions faster so it’s a lot quicker to react
