Answer:
175 kJ
Explanation:
Activation energy can be defined as the potential energy that is needed to change reactants to products. This is the minimum energy required for the chemical reaction to take place. Thus, using the given figure:
Activation energy = activation complex - reactant energy
In the given figure, activation complex = 400 kJ
reactant energy = 225 kJ
Therefore:
Activation energy = 400 - 225 = 175 kJ
The answer is B, sodium is an element.
Answer:
There are five signs of a chemical change:
Colour Change.
Production of an odour.
Change of Temperature.
Evolution of a gas (formation of bubbles)
Precipitate (formation of a solid).
