Question

W
2. True and False statement
(1) Chemical changes are generally accompanied by an exchange of energy.
(1) A physical change is usually reversible.
(iii) When a magnesium ribbon burns brilliantly in air a physical change takes
place.
Ammonium chloride dissolves in water with the absorption of heat. This is an
exothermic.
(v) To balance a chemical equation, can we change the formula of either reactants
or products?
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Answer 1

Answer:

hi here is your answer .....

1) true

2) true

3) false

4) false

Answer 2

Answer:

The Correct Answers are listed as below:

1. Chemical changes are generally accompanied by an exchange of energy. - True
2. A physical change is usually reversible. - True
3. When a magnesium ribbon burns brilliantly in air, a physical change take place. - False
4. Ammonium chloride dissolves in water with the absorption of heat. This is an exothermic. - False
5. To balance a chemical equation, can we change the formula of either reactants or products? - False

Explanation:

1. In a chemical change, energy is exchanged to break the chemical bonds in order to form the corresponding product.
2. Physical changes are always reversible. It means we can always obtain the matter's original shape and size. Example : blowing air into a balloon, melting of wax candle, etc.
3. When a magnesium ribbon is burned in presence of oxygen, it is basically a chemical change, not a physical one.
4. When Ammonium Chloride dissolves in water by absorbing heat, the process in Endothermic as heat is involved.
5. We can't change formula of reactants or products no matter what. We can multiply them by numbers like 3,2,4,etc to balance the equation.