Question

Write the factors that can be used to determine whether a chemical reaction has taken place or not. Explain each factor with about 3-4 lines.

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Answer 1

Answer:

The rates at which reactants are consumed and products are formed during chemical reactions vary greatly. We can identify five factors that affect the rates of chemical reactions: the chemical nature of the reacting substances, the state of subdivision (one large lump versus many small particles) of the reactants, the temperature of the reactants, the concentration of the reactants, and the presence of a catalyst

Answer 2

Answer:

1. If temperature has changed

2. If color has changed

3. If Gas is produced

4. If a change in state occurs

5. Change in color

Explanation:

1. If temperature has changed:

In this case on adding a substance to another if there is increase or decrease in temperature then we know that a reaction has occured. These are known as exothermic and endothermic reactions.

2.If Color has Changed:

In this case if the color of solution changes. For eg:

                 Pb(NO3)2 + KI ---> PbI + KNO3

Here solution changes to yellow in color.

3. Precipitate:

In case of certain chemical reactions when we dissolve two or more solutions we might see a deposit of precipitate, an entirely new feature.

4.Change in State:

A yet common eg of a burning candle is a chemical reaction too.  We might know that the wax melts or just evaporate. Therefore, in this, we see that the state changes from one state to another.

5. Gas Produced:

In this we  can see after reaction gas is produced

Classic Eg,

                    Acid + Metal Carbonate/Bicarbonate---> Salt + CO2 + H2O

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That my friend could be an answer for you.