chemistry specification part 2 Flashcards
what salts are formed when halogens react with some metals
metal halides
complete the statement:
halogens can react with hydrogen to form…
hydrogen halides that are soluble e.g hydrochloric acid in water
if you add the same halogen to their solution e.g chlorine water with potassium chloride solution or bromine water with potassium bromide what will happen
no reaction will occur because it cant displace itself
why are noble gases inert?
they have full outer shells so they are completely unreactive
Explain how the uses of noble gases depend on their inertness, low density and/or non-flammability
-provide an inert atmosphere. Argon is non-flammable and stops the very hot filament in a light bulb from burning away
-argon and helium can be used to protect metals from being welded. Stops metal from reacting with oxygen.
-helium is used in airships and party balloons because of its lower density than air.Non-flammable so safer alternative to hydrogen gas
Describe the pattern in the physical properties of some noble gases and use this pattern to predict the physical properties of other noble gases
boiling point and density increase as you go down the Group 0
what is the rate of reaction formula
amount of reactant used or amount of product formed divided by time
what is one way a rate of reaction experiment can be measured-precipitation
Mix two see through reactant solutions and put the flask on a piece of paper with a mark on it.
Observe the mark through the mixture and measure how long it takes for the mark to disappear. The faster it is the faster the reaction.
However, the result is subjective as the mark can disappear at any time for different people
what is one way a rate of reaction experiment can be measured-change in mass ( gas give off)
you can measure the rate of a reaction that produces a gas using a mass balance. The gas is released, the lost mass is measured and the quicker the reading the faster the reaction. We add cotton wool at the top of the flask to let the gas out but stop reactants from flying out.You know it’s finished when the mass stops decreasing.However, if the gas is harmful you need to do this in a fume cupboard
what is one way a rate of reaction experiment can be measured-volume of gas is given off
involves a gas syringe to measure the volume of gas given off. The more gas is given off during a time interval, the faster the reaction, You know it’s finished when no more gas is produced .However, you need to use the right size syringe because if the reaction is too vigorous you can blow the plunger off the syringe
