Find the mean by direct method .
No. of stolent
2
Marks
3
5
6
2
5
8
4
2
WANA
Answers
Step-by-step explanation:
What is a pure substance? Name the types of pure substances.
Answer: Any substance is said to be pure if and only if it is made up of single type of particles means all the particles of that substance should be of same chemical nature. For example water, sugar, salt, Sodium, Tin etc.
There are two types of pure substances that are Elements and Compounds.
Examples of elements are: Iron, Silver, Gold, Mercury etc.
Examples of compounds are: Water, Carbon dioxide, methane, vinegar etc.
What is a mixture? Name the types of mixtures? What is the difference between them?
Answer: A mixture is a combination of two or more substances (elements or compounds) which is not done chemically.
Mixtures are two types Homogeneous Mixtures and Heterogeneous mixtures.
Homogeneous Mixtures: A Homogeneous mixture has a uniform composition of its components throughout its mass. It does not have visible boundaries of separation between the various components. For example a sugar solution or a salt solution.
Heterogeneous Mixtures: A Heterogeneous mixtures does not have a uniform composition throughout its mass also it has visible boundaries of separation between various components. For example mixture of sand and water.
What is a solution? Write its properties.
Answer: A solution is a homogeneous mixture of two or more substances. A solution has a solvent and a solute as its components.The component of the solution that dissolves the other component in it (usually the component present in larger amount) is called the solvent.The component of the solution that is dissolved in the solvent (usually present in lesser quantity) is called the solute.
Properties of a solution
• A solution is a homogeneous mixture.
• The particles of a solution are smaller than 1 nm (10-9 metre) in diameter. So, they cannot be seen by naked eyes.
• Because of very small particle size, they do not scatter a beam of light passing through the solution. So, the path of light is not visible in a solution.
• The solute particles cannot be separated from the mixture by the process of filtration. The solute particles do not settle down when left undisturbed,
that is, a solution is stable.
Concentration of Solution: Concentration of a solution is the amount of solute present in the given amount of solution. The concentration of a solution can be determined by the following ways:
class 9 IS Matter Around Us Pure Science ncert solutions
4.375
Step-by-step explanation:
sum of all numbers,
3+5+6+2+8+4+2= 35
mean = sum of the numbers/total number
= 35/8
=4.375 ans