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Chemistry

A Level

Explain how a catalyst can effect the rate of a forward and reverse reaction.

A catalyst can provide a different mechanism or pathway for a chemical reaction through stabalistion of the transition state. The catalyst will lower the activation energy of the reaction meaning a greate...

Answered by Kieran N. • Chemistry tutor

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Palladium acts as a heterogeneous catalyst in the reaction between an alkene with hydrogen by providing an alternative reaction route. Describe the stages of this reaction route. (3 marks)

The detail required for many A-level questions is indicated in the number of marks available. As this question awards 3 marks, 3 separate points must be made. For example, the first stage of a heterogeneo...

Answered by Amy S. • Chemistry tutor

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State the relative charge and relative mass of a proton, of a neutron and of an electron. In terms of particles, explain the relationship between two isotopes of the same element. Explain why these isotopes have identical chemical properties.

Proton: Relative Mass = 1, Relative Charge = +1Neutron: Relative Mass = 1, Relative Charge = 0Electron: Relative Mass = ~1/1870, Relative Charge = -1
Isotopes vary in the number of neutrons and there...

Answered by Edward P. • Chemistry tutor

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Explain the trend in first ionisation energy along period 3

Going across a period there is generally an increase in first ionisation energy. This is because there are more protons in each nucleus leading to a greater positive charge and stronger electrostatic forc...

Answered by Jasmine D. • Chemistry tutor

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Explain the trend of first ionisation energy down a group.

The first ionisation energy is the energy required to remove one electron from an atom. Down a group, there are more electron shells surrounding the nucleus, which results in a greater shielding from the ...

Answered by Rachael W. • Chemistry tutor

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