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What is the usual symbol for (a) an electron (b) a proton, and (c) a neutron?

Which of the following ions is mono-atomic?

In gases, the volume of particles is _______ as compared to inter-molecular distance between them, Hence gases can be easily compressed.

Hydrogen is produced in two different reactions in totally different environments.Will the atoms of hydrogen in the two reactions have same mass and chemical properties?

Which of the following are characteristic properties of gases?

The number of moles of molecules present in 288 g of oxygen gas is:

Based on what is the chemical formula of an ionic compound determined?

How to find the atomic mass of any element?

The formula of iron (III) sulphate is _______ .

State the law of conservation of mass. Give one example to illustrate this law.

Give two postulate of the Bohr's atomic model. [3 MARKS]

What are the rules for writing a chemical formula? [3 MARKS]

Which of the following represents the anode half-cell reaction for the following galvanic cell: $Cu\left(s\right)|C{u}^{2+}\left(aq\right)||A{g}^{+}\left(aq\right)|Ag\left(s\right)$

Which is the monomer of neoprene among the following?

What are the products of heating sodium azide in the air?

(a) Define a chemical reaction.

(b) What happens during a chemical reaction ?

(c) What do you understand by a chemical bond ?

Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by the inverting a test tube over it. Then he react the gas with moist Litmus paper. Write a balanced chemical equation for the reaction taking place.

Which of the following will show tyndall effect

a. Salt solution

b. Milk

c. Copper sulphate solution

d. Starch solution

Explain why :

(a) Water is an excellent liquid to use in cooling systems.

(b) A solution is always clear and transparent.

(c) Lakes and rivers do not suddenly freeze in the winters.

(d) The solute cannot be separated from a solution by filtration.

(e) Fused $CaC{l}_2$ or conc. $H_{2}S{O}_4$ is used in a desiccator.

(f) Effervescence is seen on opening a bottle of soda water.

Which of the following fluorides does not exist?

Why does water become cold if we add some ice cubes in it?

Calculate the amount of sodium sulphate required to prepare it's 20% (mass percent) solution in 100 g of water?

Name the property :

(a) which allows metals to be hammered into thin sheets.

(b) which enables metals to be drawn into wires.

Why does $C{O}_2$ turn lime water milky?

Name the change seen in the picture.

Assertion: The metallic character increases as we go down the group.

Reason: Increase in size decreases the ionisation energy.

Explain why there is no rise in temperature of a substance when it undergoes a change of state through heat is supplied continuously.

There are four substances W, X, Y and Z. The sbustance W is a dark violet solid having diatomic molecules. A solution of W in alcohol is used as a common antiseptic C. The subsatance X is a white solid which is usually recovered from sea water on a large scale. The substance Y is a white solid which is insoluble in water and used in the form of small balls for the safe storage of woolen clothes. The substance Z is a yet another white solid which is used in making commonly used dry cells.

(a) Name (i) W (ii) X (iii) Y and (iv) Z.

(b) Out of W, X, Y and Z, which substace/substances can undergo sublimation?

(c) Which substance is organic in nature?

(d) What is the name of substance C?

(e) Which substance belongs to the halogen family?

The Law of conservation of mass states :

How many moles are present in 80 grams of Oxygen gas?

Question 23.
Which among the following is not a base ?
(a) $\text{NaOH}$
(b) $\text{KOH}$
(c) ${\text{NH}}_4\text{OH}$
(d) ${\text{C}}_2{\text{H}}_5\text{OH}$

Many indigestion mixtures are suspensions. What do the instructions written on the bottle of an indigestion mixture tell us before taking the mixture, and why?

Duralumin is an alloy of ?

Give one example:-

Colloid in the form of areosol ( solid in liquid)

Number of C–H and C–C bonds respectively in compound given below are-