Unit 1 Chemistry

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unit 1chemistry

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Reaction rates could be speed up by:-

decreasing particle size, increasing concentration, increasing temperature

Catalysts speed up reactions without...and can be...

...being used up...recovered unchanged at the end of reaction

a mole of a substance is... (is equal to)

...it's formula mass in grams (GFM)

1000cm^3 equals to

one litre

molecules can react if they've got enough...

...activation energy

What is an activated complex?

the unstable arrangement of atoms form at the maximum of potential energy.

homogeneous catalysts are in the same state as what?

as the reactants

Heterogeneous catalysts are in the same? or different? state as the reactants

different

what are the effects of concentration?

no of particles increase which means more chances of collisions

What are the effects of particle size?

A large surface area means higher chance of collision

Is the haber process an example of a heteroegenous catalyst?

yes

describe one of the gas conversions in a catalytic converter

NO-->N2 NO2-->O2 CO-->CO2

Why must lead-free petrol (unleaded) be used?

Because the lead atoms produced stick to the surface of the catalyst and stop the converter from working

What is activation energy?

a certain amount of energy in order for a reaction to occur

An exothermic reaction ______ ___ energy.

gives out

An endothermic reaction _____ __ energy.

takes in

When an acid reacts with an alkali or other base what occurs?

Neutralisation

What is measure of chemical energy stored within substances?

Enthalpy

Acid + _______ --> ____ + water

alkali, salt

what is the ionic equation of a neutralisation reaction

H(positive) + OH(negative) --> H2O

The enthalpy of _____ is the enthalpy change that occurs when one mole of a substance dissolves completely in water

solution

Enthalpy of _________ is the enthalpy change per mole of water formed when an acid is neutralised by an alkali.

neutralisation

what is the concentration of a substance is measured in?

moles per litre

volumes of gases are directly proportional to the ...?

number of moles

Name the the 7 diatomic molecules?

I2, Br2, Cl2, F2, O2, N2, H2