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Why do gases are transparent?

If you see a person whose clothes are on fire, how will you extinguish the fire ? Give reason for answer.

The phase transition in which a liquid turns into a solid is called _________.

State the main postulates of the kinetic theory of matter.

Match the following:

$\begin{array}{cccc}\left(i\right)& \text{Can have variable composition of constituent elements}& \text{(A)}& \text{Compound}\\ \text{(ii)}& \underset{–}{}\underset{–}{}\underset{–}{}\text{is new substance formed due to reaction of two constituent elements}& \text{(B)}& \text{Mixture}\\ \text{(iii)}& \text{Constituent elements can be separated easily}& \text{(C)}& \text{Element}\\ \text{(iv)}& \text{Can be separated only by chemical or electrochemical reactions}& & \\ \text{(v)}& \text{Composition is always fixed}& & \\ \text{(vi)}& \text{Shows properties of constituent elements}& & \end{array}$
The correct pairs are:-

Assertion: Aluminium foil cannot be used in $\alpha$ - particle scattering experiment
Reason: Aluminium is highly malleable metal.

What happens when :

(a) A lit splinter is introduced into a jar containing carbon dioxide?

(b) Moist blue litmus paper is placed in a jar containing carbon dioxide?

(c) Carbon dioxide is passed through lime water first in small amounts and the excess?

(d) A baking mixture containing baking powder is heated?

(e) A soda water bottle is opened?

Which is the correct statement about a proton?

Which of the following led to the discovery of protons?

Which among the following alloys contain zinc as one of its constituents?

${Fe}_2{O}_3$ + $2Al$ $\to$ ${Al}_2{O}_3$ + $2Fe$

This reaction is an example of :

Write the dispersed phase and dispersed medium of jelly, cheese and butter.

How does pure hydrogen gas burns?

What are the important formulas of this chapter?

Give examples of substances which burn to give a flame. Why do some substances burn without a flame? [3 MARKS]

Which of the following substances burns spontaneously?

Find out the catalyst in the following reaction.

How can you help reduce air pollution at the individual level ?

Which of the following describes a mixture?

Which of the following is an example of a visual indicator?

Match the statements in Column A with those in Column B.

$\begin{array}{cccc}& \text{Column A}& & \text{Column B}\\ 1.& \text{A metal which reacts with cold water to form hydrogen.}& 1.& \text{Reduction.}\\ 2.& \text{A gas which is inflammable and a non-supporter of combussion.}& 2.& \text{Hydrogenation.}\\ 3.& \text{A process in which vanaspati ghee is prepared from vegetable oils.}& 3.& \text{Oxidation.}\\ 4.& \text{The removalof hydrogen or addition of oxygen.}& 4.& \text{Sodium.}\\ 5.& \text{The addition of hydrogen or removal of oxygen.}& 5.& \text{Hydrogen.}\end{array}$

When will the cation not form during electrolysis?

Phosphorus is highly inflammable; in a matchstick, it ignites by ___ .

Name the protein which is the chief component of wool fibres. [1 MARK]

Write balanced chemical equation for the reaction that takes place during respiration. Identify the type of combination reaction that takes place during this process and justify the name. Give one more example of this type of reaction.

Which of the following statements is most suitable as the postulates of Thomson’s model of an atom?

Which of the following is correct about Bohr's Atomic model?

a brief history of atomic structure(Bohr's)

What are gamma rays??

From what device are we able to atomic or the sub-atomic particles

A ________ solution in which no more solute can be dissolved in a definite amount of solvent at agiven temperature.

Select the metal present in sodium hydroxide from the following:

Water pollution can be classified as

A force of 20 N acts on a body and displaces it 2m along the direction of force. Then the work done by the force is:

Which of the following can be used to synthesize $S{O}_2$?

Match the entries of column I with column II

Zone refining is a method to obtain:

Respected sir,

In the chapter of water, I didn't understand the masks of the water. The percentage of earth water then fresh water or ice sheets ground water, etc. Can you explain it briefly to me.

Sincerely,

Syed jaabir

Metals react by :

It is a hot summer day, the first thing that comes to anyone's mind is swimming. So what type of costume would you put on before entering the pool?

Which among the following are the four elements according to the Greek philosopher "Empedocles"?

Which plant was used by European cloth manufacturers as an alternative to indigo?

Answer the following questions :

(a) What is destructive distillation? What are the products formed due to the destructive distillation of coal?

(b) Why are wood charcoal used in water filters and gas masks?

(c) How is wood charcoal made locally? What other substances are formed in the process?

(d) How many carbon atoms are there in Buckminster fullerenes?