A catalyst is an agent that alters the rate of a chemical reaction without undergoing any permanent chemical change in the reaction. For example, nickel, platinum or palladium is used as a catalyst in the hydrogenation reaction of unsaturated compounds.

Balance the following chemical equations: (a) Na + O 2 → Na 2 O (b) K + H 2 O → KOH + H 2

(a) A balanced chemical equation is a chemical equation where the number of atoms involved in the reactants side is equal to the number of atoms on the products side. The balanced chemical equation for the given equation is: 4 Na + O 2 → 2 Na 2 O Sodium is a very reactive metal, it tends to react with oxygen to form sodium oxide. (b) The balanced chemical equation for the given equation is: 2 K + 2 H 2 O → 2 KOH + H 2 This is a single replacement reaction where the potassium atom replaces the hydrogen in H 2 O .

Balance the following chemical reaction. C 2 H 6 + O 2 → CO 2 + H 2 O

The balanced chemical reaction is as follows: 2 C 2 H 6 + 7 O 2 → 4 CO 2 + 6 H 2 O Here two moles of ethane reacts with seven moles of oxygen to release four moles of carbon dioxide. This is a combustion reaction in which any substance reacts with oxygen in the presence of air to release carbon dioxide and heat energy.

Balance the following chemical reaction. (i) Mg + N 2 → Mg 3 N 2

The balanced chemical reaction is as follows: 3 Mg + N 2 → Mg 3 N 2 In this reaction, oxidation of Mg and reduction of nitrogen is taken place. This represents a redox reaction. Magnesium is oxidized, and dinitrogen is reduced.

Balance the following equation: CuS + HCl → CuCl 2 + H 2 S

The balanced chemical equation is as follows: CuS s + 2 HCl aq → CuCl 2 aq + H 2 S g When copper sulphide reacts with hydrochloric acid, copper chloride will form and hydrogen sulphide gas will be evolved.

Balance the following equation: Fe + H 2 O → Fe 3 O 4 + H 2

The balanced equation is as follows: 3 Fe + 4 H 2 O → Fe 3 O 4 + 4 H 2 When iron reacts with oxygen and water, iron oxide is formed. This iron oxide is commonly known as rust and the process is known as rusting.

Balance the following chemical equations: (a) H 2 + O 2 → H 2 O (b) MnO 2 + HCl → MnCl 2 + Cl 2 + H 2 O

A chemical equation in which the number of atoms of each element is equal on both sides of the equation is known as a balanced chemical equation. (a) When hydrogen reacts with oxygen, water is formed. The balanced chemical equation is as follows: 2 H 2 ( g ) + O 2 ( g ) → 2 H 2 O ( l ) (b) Manganese dioxide reacts with hydrochloric acid and forms manganese chloride, chlorine gas and water. The balanced chemical equation is as follows: MnO 2 s + 4 HCl aq → MnCl 2 s + Cl 2 g + 2 H 2 O l

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Green copper carbonate powder was heated. The powder started bubbling and it turned black. One of the products was gas. How can you tell?

Important Questions on Chemical reactions and Equations

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Translate the following statement into a chemical equation and then balance it.

Hydrogen gas combines with nitrogen to form ammonia.

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Translate the following statement into a chemical equation and balance it:

Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

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Translate the following statement into a chemical equation and then balance it.

Hydrogen sulphide gas burns in the air to give water and sulphur dioxide.

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Draw the diagram of the arrangement of apparatus used to show the reaction of zinc granules with dilute sulphuric acid and testing hydrogen gas by burning. Label the soap solution.

EASY

Science>Chemistry>Chemical reactions and Equations>Chemical Changes and Equations

Why should a magnesium ribbon be cleaned before burning in air?

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Science>Chemistry>Chemical reactions and Equations>Chemical Changes and Equations

Translate the following statement into chemical equation and then balance them.

Hydrogen sulphide gas burns in air to give water and sulphur dioxide.

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Science>Chemistry>Chemical reactions and Equations>Chemical Changes and Equations

Why should a magnesium ribbon be cleaned before burning in the air?

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Science>Chemistry>Chemical reactions and Equations>Chemical Changes and Equations

Which one of the following processes involves a chemical reaction?

EASY

Science>Chemistry>Chemical reactions and Equations>Chemical Changes and Equations

What is a catalyst?

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Science>Chemistry>Chemical reactions and Equations>Chemical Changes and Equations

Translate the following statement into chemical equation and balance it:
Hydrogen gas combines with nitrogen to form ammonia.

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Science>Chemistry>Chemical reactions and Equations>Chemical Changes and Equations

Draw the diagram of the arrangement of apparatus used to show the reaction of zinc granules with dilute sulphuric acid and testing hydrogen gas by burning. Label the delivery tube.

HARD

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Balance the following chemical equations:

(a) $Na + O_{2} \to {Na}_{2} O$

(b) $K + H_{2} O \to KOH + H_{2}$

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Balance the following chemical reaction.

$C_{2} H_{6} + O_{2} \to {CO}_{2} + H_{2} O$

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Science>Chemistry>Chemical reactions and Equations>Chemical Changes and Equations

Translate the following statement into chemical equation and then balance them.

Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

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Balance the following chemical reaction.

(i) $Mg + N_{2} \to {Mg}_{3} N_{2}$

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Balance the following equation:

$CuS + HCl \to {CuCl}_{2} + H_{2} S$

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Balance the following equation:

$Fe + H_{2} O \to {Fe}_{3} O_{4} + H_{2}$

EASY

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Translate the following statement into a chemical equation and balance it:
Zinc reacts with sulphuric acid to give zinc sulphate and hydrogen gas.

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Balance the following chemical equations:

(a) $H_{2} + O_{2} \to H_{2} O$

(b) ${MnO}_{2} + HCl \to {MnCl}_{2} + {Cl}_{2} + H_{2} O$

EASY

Science>Chemistry>Chemical reactions and Equations>Chemical Changes and Equations

Two chemical mixed by the laboratory assistant in the laboratory are Barium chloride and potassium sulphate. Write a balanced Chemical Equation for the above reaction.

Green copper carbonate powder was heated. The powder started bubbling and it turned black. One of the products was gas. How can you tell?

Important Questions on Chemical reactions and Equations

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