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33 Science -- Chemical Reaction

Differentiate between.Reactants and productsWord equation and formulae equationCombination reaction and decomposition reactionPositive catalyst and negative catalyst

Differentiate between.


  1. Reactants and products

  2. Word equation and formulae equation

  3. Combination reaction and decomposition reaction

  4. Positive catalyst and negative catalyst

1 Answers

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a. Reactants and products.

ReactantsProducts
The chemicals that undergo chemical changes are reactants.The chemicals that are formed as a result of the reaction are products.
These are the chemicals before the reaction between them occurs.These are the chemicals after the reaction between them occurs.

b. Word equation and formulae equation.

WordFormulae
It is the representation of chemical equations by words.It is the representation of chemical equations by symbols.
It is less informative.It is more informative.
It is longer and non-convenient.It is shorter and convenient.

c. Combination reaction and decomposition reaction.

CombinationDecomposition
In this reaction, different reactants are combined to form a single product.In this reaction, a single reactant is decomposed to form multiple products.
It occurs either in the presence or absence of heat.It occurs in the presence of heat only.

d. Positive catalyst and negative catalyst.

PositiveNegative
It increases the rate of a chemical reaction.It decreases the rate of a chemical reaction.
It is used to accelerate the reaction.It is used to slow down the reaction.
Mn02 is an example.Glycerine is an example.

More questions on Chemical Reaction

What is meant by a chemical reaction? Give any 2 examples.

The combination or displacement that occurs in themolecules of matter during a chemical changecalled a chemical reaction.Any two examples are:

  1. 2H2 + 02 -------> 2H20
  2. H2SO4 + Zn ---------> ZnSO4 + H2

Define word equation with any two examples.

A chemical reaction expressed by writing the fullnames of reactants and products is called a wordequation. For example:

Hydrogen + oxygen ----------->Water

What is a chemical equation? Give any 2 examples.

A chemical equation is an equation that representsthe chemical reaction with the symbols and molecularformulae of the reactants and products.

For example: 2H2+ 02 --------> 2H2O

What are reactants and products? Write with an example of each.

The elements or compounds that take part in a chemicalreaction are reactants and the elements or compoundsthat are formed as a result of a chemical reaction arecalled products.

for example

H2SO4 + Zn ----------> ZnSO4 + H2

ReactantsProducts

What is balanced chemical eqn? Give example.

A chemical eqn. which contains an equal number ofatoms of each element in both reactant and productside is called balanced chemical eqn.

Example: 2H2 + O2 --------> 2H2O

Write any three pieces of info that can be obtained from a balanced chemical eqn.

Anythree pieces of info that can be obtained froma balanced chemical eqn are:

  1. The type of chemical reaction.
  2. The name and symbol of reactants and products.
  3. The total number of atoms of reactants and products.

Name the four factors that bring about a chemical change.

Four factors that bring about a chemical change are:

> Heat > Catalyst
> Light >Solution
> Pressure > Electricity

What is a catalyst? Define +ve and -ve catalyst with examples of each.

A catalyst is a chemical substance that increases ordecreases the rate of a chemical reaction without takingpart in a chemical reaction.

The +ve catalyst is the chemical substance thatincreases the rate of a chemical reaction. For example MnO2.Thecatalyst is the chemical substance thatdecreases the rate of a chemical reaction. For exampleglycerine.

What combination reaction? Give example.

A chemical reaction in which two or more reactantsare combined together to give a single product is calleda combination reaction.Examples are:

C + O2 --------> CO2
C + 2H2 ---------> CH4

What is decomposition reaction? Give any two examples.

A chemical reaction in which a single reactant isbroken down into two or more products called adecomposition reaction.For example:

CaCO3 -------> CaO + CO2
CuCO3 -------> CuO +CO2

Define displacement reaction. Also, state the types of displacement reaction.

A chemical reaction in which an atom of a compoundis displaced by anotherelement is called a displacementreaction. Its types are:

  1. Single displacement rxn.
  2. Double displacement rxn.

What meant by the acid-base reaction? Why it is called a neutralization reaction?

A chemical reaction in which aid and base reacttogether to gee salt and water is called an acid-basereaction.

It is called a neutralization reaction because the acidicand basic nature of compounds is neutralized duringthe reaction.

Define gram atomic weight and gram molecular weight?

The atomic weight of an element expressed in grams iscalled gram atomic weight.

The molecular weight of a substance expressed ingrams is calledmolecular weight.

Define one mole of a substance. What is Avogadro's number?

The amount of a substance that contains 6.023 X 1023atoms or ions is called moles.

Avogadro's number is the number of particlesin one mole of a substance.

NA =6.023 X 1023

Why is the burning of magnesium in the air called a combination reaction?

The burning of magnesium in the air conducts that reactionwhere magnesium and oxygencombine to formmagnesium oxide. As two elements combine each other, it iscalled a combination reaction.

2Mg + O2 ------> 2MgO

 An acid-base reaction is also called a neutralization reaction. Why?

We know, a chemical reaction in which an acid and basereact together to give salt and water is called an acid-basereaction. Here acidic and basic nature et compounds areneutralized. So, it called a neutralization reaction.

Electrolysis of water called decomposition reaction. Why?

We know, water breaks down into hydrogen andoxygen during its electrolysis. As two elementsdecompose themselves in this chemical reaction, it is called adecomposition reaction.

2H20 --------> 2H2 + O2

What is meant by the rate of a chemical reaction? Let any four factors that affect the rate of a chemical reaction.

The positive change in the concentration of areactant or a product per unit time is called therate of a chemical reaction.Any four factors that affect the rate of a chemicalreaction are:

  1. The concentration of reactants
  2. Temperature
  3. Physical nature of reactants
  4. Chemical nature of reactants

Write down the effect of temperature and catalyst on the rate of a chemical reaction.

An increase in temperature increases the rate e chemicalreaction whereas a decrease in temperature decreases the rateof a chemicalreaction.

Positive catalyst increases and negative catalystdecreases the rate of a chemical reaction.

How does the concentration of sodium thiosulphate affect the rate of the chemical reaction between hydrochloric acid and sodium thiosulphate?

When theconcentration of Sodium thiosulphatewas increased therateofreactionincreased and the time taken to reach equilibrium decreased, so therefore therateofreactionis directly proportional to theconcentration.So rate of reaction increases.


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