chemical reaction grade 9

In the thermal decomposition reactions, the compound decomposes by heat

• simple components.

• primary elements.

• other compounds.

• all the answers.

On heating copper carbonate, the colour changes from.........

• blue to black.

• green to black.

• black to green.

• green to blue.

Most metal sulphates decompose when they are heated to metal oxide and...........gas.

• 0₂

• SO₂

• SO₃

All of

the following metals replace

hydrogen of an acid except...........

• Sn

• Zn

• Al

• Au

Double substitution reactions between two salt solutions are accompanied by formation of .........

• a metal.

• precipitate.

• an oxide.

• a nonmetal.

The reaction : Cl₂ + 2e = 2Cl ^- , represents process.

• decomposition

• oxidation

• reduction

• substitution

When sodium atom loses an electron from its outermost energy level, it becomes............

• oxidized only.

• reducing agent only.

• reduced only.

In oxidation and reduction reactions, the number of lost electrons is ------- of gained electrons.

The breaking up of bonds between molecules of the reactants and formation of

new bonds between the molecules of the products

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They are chemical reactions in which one of the elements substitutes another less active element in a solution of one of its compounds.

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