chem quiz 1 Flashcards
Describe the difference between mass number and relative atomic mass
mass number is the number of protons and neutrons in one atom
relative atomic mass is an average value that takes account of isotopes
A student is adding ammonium chloride to water,creating an endothermic reaction. They want to know how the mass of ammonium chloride added affects the temperature change outline a method to do this. Ensure a valid conclusion
Measure a specific mass of ammonium chloride
use a measuring cylinder to measure a set volume of water and pour it into a polystyrene cup
measure the temperature of the water
add the ammonium chloride to the water
Measure the highest temperature reached by the water
Repeat the experiment with other masses of ammonium chloride
Ensure that the following variables are kept constant: particle size of ammonium chloride,volume of water and source of water
In this reaction, what has been oxidised and what has been reduced?
Cl2 + 2Br- —–> Br2 + 2Cl-
Cl2 has been reduced
Br- has been oxidised
State how a mixture of a solid and a liquid can be separated
filtration
Explain why the anode(positive electrode) needs to be continually replaced in the electrolysis of a aluminium oxide
Oxygen is produced at the anode(positive electrdode)
The oxygen reacts with the anode(positive electrode) which is made of carbon
which forms carbon dioxide
Causing the anode(positive electrode) to wear away
In a reaction between the 3 solutions, a solid is produced.Name the experimental method that can be used to measure the rate of reaction
The disappearing cross method
Name the type of process in which mixtures are separated into their components
physical process
In terms of bond energies, explain why some reactions are exothermic
more energy is released when forming bonds in products than is taken to break the bond in reactants
