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Question 23

You are provided with four test tubes containing sugar solution, baking soda solution, tamarind solution, salt solution. Write down an activity to find the nature of each solution

Question 03

Match the items given in Column A with that in Column B
$\begin{array}{cc}ColumnA& ColumnB\\ Milk,curd,paneer,ghee& Eatotheranimals\\ Spinach,cauliflower,carrot& Eatplantsandplantproducts\\ Lionsandtigers& arevegetables\\ Herbivores& areallanimalproducts\end{array}$

Give two reasons why is it not possible to see an atom with our naked eyes? [2 MARKS]

Which among the following methods is most suitable to separate a mixture of salt and ammonium chloride?

Untreated sewage contaminates Ganga because:

Two substances A and substance B when brought together forms a substance C with liberation of heat .the properties of C are entirely different from those of A and B. What is substance C ?
a) metal
B) element
C) compound
D) mixture

Which of the following quantity does not always expand on heating?

Select the materials that clog drains:

Match the following:

$$\begin{array}{cccc}\left(\text{i}\right)& \text{Water}& \left(\text{A}\right)& \text{Compound}\\ \left(\text{ii}\right)& \text{Hydrogen}& \left(\text{B}\right)& \text{Element}\\ \left(\text{iii}\right)& \text{Salt}& & \\ \left(\text{iv}\right)& \text{Gold}& & \\ \left(\text{v}\right)& \text{Carbon dioxide}& & \\ \left(\text{vi}\right)& \text{Iron}& & \end{array}$$
The correct pairs are:-

During a chemical reaction, if the products have more chemical energy than the reactants,

Which among the following is not used to spin thread from fibres?

A particular region in some state of India is observing a constant decrease in the water table. Identify the most probable reason for the same.

Why is sodium stored in kerosene oil?

Question 4
Describe the steps involved in getting clarified water from wastewater.

Which of the following are the properties of the natural gas?

Law of definite proportions is given by:

Why do you think nurdles are extremely dangerous when present in wastewater?

When zeolite is treated with hard water, the sodium ions are exchanged with:

What are artificial fibres mostly used in and why

The amount of heat energy required to change 1 kg of solid into liquid at its melting point is known as ______________

The activation energy for a reaction at the temperature TK was found to be 2.303 $RTJmo{l}^{-1}$. The ratio of the rate constant to Arrhenius factor is ___

Identify the chemical change.

The process in which caterpillars turn into butterflies is called ___.

Basic radicals have _____ charge and are also called as _____.

This is year 348 BC. Aristotle is a famous Greek philosopher and scientist. One day he suddenly wakes up into the future - The year 2017. He observes that the world has changed a lot.
Out of the following observations made by him, which observations are examples of change?

Which gas is put in the bubble sheet?

The electron in a hydrogen atom makes transition from M shell to L. The ratio of magnitudes of initial to final centripetal acceleration of the electron is

An iron rod is heated. Which of the following statements is incorrect?

What is the charge of $Mg$ in $Mg{Cl}_2$?

How can you prevent ground water depletion?

Which are the methods used for prevention of corrosion?

Weight and mass are _____.

can salt be acidic , basic or neutral ?

The word ___ comes from the Latin word 'acere' which means sour.

Four students have their own opinion about reversible and irreversible changes. Who among the following is correct?

Rohan: Both physical and chemical changes are reversible.

Sam: Both physical and chemical changes are irreversible.

Tom: Physical changes are irreversible and chemical changes are reversible.

Riah: Chemical changes are irreversible and physical changes are reversible

Which one of the following represents carbon dioxide?

A decomposition reaction is generally represented as_______ .

Question 6

Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?
(a) It is more than 7 m high
(b) It weighs about 6000 kg
(c) It was built more than 1600 yrs ago
(d) It has no rust after such long period

Question 8 (a)
Explain why:
(a) An antacid tablet is taken when you suffer from acidity.