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Chemical Reactions and equations

Total questions: 15

Worksheet time: 8mins

Name
Class
Date
1.

Why should we rub a Magnesium ribbon with sand paper before using it?

a)

To remove the layer of carbon-di-oxide formed on it.

b)

To remove the layer of chlorine formed on it.

c)

To remove the layer of oxygen formed on it.

d)

To remove the layer of neon formed on it.

2.

Magnesium and oxygen react with each other and form

a)

Magnesium di oxide.

b)

Magnesium triphosphate

c)

Magnesium oxide.

d)

Magnesium Hydroxide

3.

What is the chemical equation of Aluminium Hydroxide?

a)

Al2O3Al_2O_3

Al2

​O3

​

b)

Al3O2Al_3O_2

Al3

​O2

​

c)

Al(OH)2Al(OH)_2

Al(OH)2

​

d)

Al(OH)3Al\left(OH\right)_3

Al(OH)3

​

4.

A chemical reaction in which two or more substances combine with each other to form a single substance is called?

a)

Double displacement reaction

b)

Displacement reaction

c)

Combination reaction

d)

Decomposition rection

5.

What is the chemical formula of Quick lime?

a)

CaO

b)

CaOH

c)

NaOH

d)

MgO

6.

What is the chemical formula of Glucose?

a)

C6H6O12C_6H_6O_{12}

C6

​H6

​O12

​

b)

C6H12O5C_6H_{12}O_5

C6

​H12

​O5

​

c)

C6H12O6C_6H_{12}O_6

C6

​H12

​O6

​

d)

C12O6H3C_{12}O_6H_3

C12

​O6

​H3

​

7.

H2+O2  =  H2OH_2+O_2\ \ =\ \ H_2O  Is an example of which reaction?

a)

Decomposition

b)

Double displacement

c)

Dispalcement

d)

Combination

8.

By which method can we decompose water molecule?

a)

Heating

b)

Electrolysis

c)

Oxidation

d)

Reduction

9.

Which of the following is not the characteristics of chemical reactions?

a)

Change in colour

b)

Change in temperature

c)

Evolution of gas

d)

None of the above

10.

Quicklime reacts with water to form?

a)

Cao

b)

Ca(OH)2Ca\left(OH\right)_2

Ca(OH)2

​

c)

NH4O2NH_4O_2

NH4

​O2

​

d)

LimeLime

Lime

11.

The substances which combine in a chemical reaction is called?

a)

Products

b)

Reactants

c)

Combining elements

d)

Refractions

12.

Why do we need to balance the chemical equations?

a)

To maintain the law of conservation of mass

b)

To maintain the law of constant proportions

c)

To maintain law of constant mass

d)

To write the chemical formula of the given compounds.

13.

Methanol is manufactured from

a)

Carbon-hydroxide

&

Hydrogen

b)

Alchohol

&

Hydrogen

c)

Sulphur

&

Carbon

d)

Carbon-monoxide

&

Hydrogen

14.

What is used a catalyst during the preperation of oxygen gas from potassium chlorate?

a)

Carbondioxide

b)

Manganese dioxide

c)

Carbon monoxide

d)

Methane

15.

Why is repiration considered a exothermic reaction?

4 lines