Question of Exercise 1

Atom and Molecule of Class 9

Question
2 moles of H2 burn to form 2 moles of H2O. The mass of oxygen used up will be

Answer

Option 1 16 g

Option 2 32 g

Option 3 2 moles

Option 4 4 moles

Frequently Asked Questions

Air is a

A: homogeneous mixture

B: heterogeneous mixture

C: compound

D: none of these

 

Solution:

Explanation:

Air is made up of a variety of gases that are evenly distributed throughout the environment. If we examine any portion of air, we will notice that its composition is consistent. Everywhere in the air, the amounts of all gases are the same.

A homogeneous mixture is one in which the components are uniformly distributed across the entire mixture. Homogeneous mixes are defined as ones that contain only one phase of matter, such as a solid, liquid, or gas. Physical separation of the components of a homogeneous mixture is difficult.

As a result, air is composed of a variety of gases, including 78.09 nitrogen, 20.95 oxygen, 0.93 argon, 0.04 carbon dioxide, and water vapours. However, they are all in the same phase. As a result, the correct answer is homogenous mixture.

 Final Answer :

Thus, option A( Homogeneousmixture)is the correct answer.

 

 

What are polyatomic ions Give examples

Solution:

Explanation: Ions with more than one atom are known as polyatomic ions.

When a number of atoms come together to form a group, polyatomic ions are formed. Covalent bonds hold it all together.

Example of polyatomic ions are

  1. SO42-
  2. OH-
  3. NH4+

Final answer: Ions having more than one atom are polyatomic ions like SO42-

 

Write the symbol of gold

Solution:

Explanation:

The chemical symbol of gold is Au, taken from the Latin word for gold - Aurum.

Final answer:

The symbol of gold is Au. 

 

State three characteristics of molecules of matter

Solution:

Explanation:

Three characteristics of molecules of matter are as follows:

1. Molecules of matter are very small in size.

2. Molecules of matter have space between them.

3. Molecules of matter are in constant random motion.

Final answer:

1. Molecules of matter are very small in size.

2. Molecules of matter have space between them.

3. Molecules of matter are in constant random motion. 

 

Classify each of the following as a homogeneous or heterogeneous

mixture: Soda water, wood, air, soil, vinegar, filtered tea.

Solution:

Explanation:

In a homogenous mixture the composition is uniform throughout whereas

in a heterogenous mixture the composition is varying in nature.

Final Answer:

Homogenous:Soda water, vinegar and filtered tea.

Heterogeneous:Wood, soil and air.

 

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