EQ's Flashcards
In sports,injury packs can be used to help after an injury. They are based around endothermic reactions.
Suggest one disadvantage about using injury packs
[1 mark]
They are made out of plastic and so they are not reusable
In sports,injury packs can be used to help after an injury. They are based around endothermic reactions.
Why would the bag feel cold during use?
The reaction is endothermic
This means that energy is transferred from the surroundings to the pack, which would cause the temperature of the surroundings to decrease
Give two limitations of using a dot and cross diagram to represent an ammonia molecule.
[2 marks]
- It doesn’t show the shape
- It is only two-dimensional
Ammonia is formed in a covalent bond
Explain why ammonia has a low boiling point.
[3 marks]
- Ammonia has small molecules
- There are weak intermolecular forces
- This means that only a little energy is required to overcome and separate the molecules
Explain why the incomplete combustion of methane is dangerous.
[2 marks]
- It produces carbon monoxide which is poisounous
- This CO binds to the haemoglobin in the blood and replaces the oxygen preventing oxygen from being carried in the blood
Explain why, in terms of the energy involved in bond breaking and bond making, the combustion of methane is exothermic
[3 marks]
- Energy is required and supplied to break the bonds (endothermic)
- Energy is released when making the bonds (exothermic)
- The energy released in making the bonds is greater than the energy required and supplied in breaking the bonds
so it’s exothermic, you MUST specify which is which first (w/ energy)
To make it obvious which is the greatest at the end!
A reaction is endothermic.
Explain why, in terms of bonds broken and bonds formed.
- The energy required and supplied to break the bonds is
- Greater than the energy released to make the bonds
This one is just bonds, so you don’t have to clarify beforehand
