How to calculate the rate of reaction

How to calculate rates of chemical reactions is very important in chemistry and applied in industries in estimating how long it will take or number of products ww will get during experimentations.

The rate of the reactions can be calculated using some basic rate of reaction formula.

Rates of reaction are used to measure how fast or slow reactions proceed and there are factors that can influence the rates of reactions.

The factors like temperature, concentration, pressure can influence the rate of chemical reaction.

Why do we increase rates of chemical reactions?

Rates of chemical reactions are usually increased or made faster in order to help the reactions finish faster and get the products on time.

Actually, some reactions are very slow like some organic reactions and may consume a lot of time while some other reactions cannot even occur on their own without aid.

Reactions that cannot occur on their own without help is called non-spontaneous reactions.

It is important to note that rates of reactions do not necessarily mean a higher yield of products but just deals with the speed of the reaction. Higher yields of products are concerned with chemical equilibrium.

In general, rates of chemical reaction is concerned with how fast or slow a reaction occur while chemical equilibrium is concerned with maximum yield of products.

Rate of Chemical Formula

The rate of chemical reaction formula is simply given by the definition of rate of reaction.

The rate of chemical reaction is defined by the amount of reactant converted t products per unit time.


Rates of Chemical reaction = Amount of reactants consumed /Time

Also, it can be related from the angle of products formed, so rate of chemical reaction can be defined from products angle.

Rates of chemical reaction is equally defined as the amounts of products formed per unit time.


Rates of chemical reaction = Amount of reactants /Time

Rates of chemical reaction units

The units of rates of chemical reaction are derived from the mathematical formula.

For example, if we have amount as mass in grams and time in seconds.

Unit will be amount/time = g/s

If we have amount as in number of moles  in mole and time in seconds

Then the unit will be mol/s

Also, if we have amount as volume in dm3 or cm3 and time in seconds

Then the unit will be dm3/s or cm3/s

Alternatively, time could be in minutes and then we can mol/m , g/m, dm3/m and cm3/m as the case may be.

Rates of reaction examples

I will solve rates of reaction questions to demonstrate how to calculate rates of chemical reactions.

1What is the rate of a chemical reaction if 20g of a reactants was consumed in 10 secondsRate = amount of reactants /Time   Rate = 20g/10s   Rate = 2g/s  
2What is the rate of a chemical reaction if 300cm3 of products was formed within 20s?Rate = amount of products /Time   Rate = 300cm3/20s   Rate = 15cm3/s  
3Calculate the rate of reaction if 200g of reactants were converted to products per 40 secondsRate = amount of reactants /Time   Rate = 200g/40s   Rate = 5g/s  
4Mg + Cl2 ===MgCl2 If 100g of Mg was converted to MgCl2 on reaction with Cl2 for 30 seconds. Calculate the rate of reaction.Rate = amount of reactants converted to products /Time   Rate = 100g/30s   Rate = 3.33g/s  
5If the rate of reaction of production of ammonia is 2.5 cm3/s. what volume of Nitrogen reacted for 20 seconds to produce the ammonia?Rate = amount of products /Time   Make amount(volume) = rate x time   Volume = 2.5 cm3/s x 20 seconds   Volume  = 50 cm3    
6Determine the time taken for 50g of reactant A to form product C if the rate of reaction is 3.5 g/s.Rate = amount of products /Time   Make Time the subject of formula   Time = Amount of reactants/Rate   Time = 50g/3.5g/s   Time = 14.29 seconds  
7How long in seconds will it take 4.5 moles of sulphuric acid to be produced if the rate is 1.2 mol/s?Rate = amount of products /Time   Make time the subject of formula   Time = amount of reactants/ rate   Time = 3.75 seconds  

To fully get a full grasp of calculating rate of chemical reactions, it is pertinent to solve other rates of chemical reaction questions and practice a lot of exercises.

However, understanding the principles in the rate of chemical equation examples we did is still vital so you can solve other questions easily.

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