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Question 14

State whether the following statements are True or False. If false, give the correct statement.
(a) The process of water seeping into the ground is called filtration.
(b) 51% of the earth’s surface is covered with water.
(c) Year 2003 was observed as the International Year of Freshwater.
(d) Snow and ice both are solid forms of water.

The law of octaves was proposed by :-

Which of these isn't a characteristic of particles of matter?

Acid + base $\to$ X + Y;

What is X and Y respectively?

What is the nature of distilled water?

Which of the following statement is incorrect about wastewater?

What is the mass percentage of hydrogen in the H₂O molecule?

Which of the following do plants obtain from the soil?

Pick the odd one.​ Give reason.​​​​​​ [2 MARKS]
Vinegar, Formic acid, Curd, Calamine

Ripening of a mango is ____

Question 19

Match the items of Column I with the items of Column II with reference to sewage.

$\begin{array}{cc}& \\ ColumnI& ColumnII\\ \left(a\right)Inorganicimpurities& \left(i\right)phosphorusandnitrogen\\ \left(b\right)Organicimpurities& \left(ii\right)nitratesandphosphates\\ \left(c\right)Nutrients& \left(iii\right)choleraandtyphoid\\ \left(d\right)Bacteria& \left(iv\right)pesticidesandherbicides\end{array}$

___ protects the Earth from ultraviolet radiations.

Question 9
Make a sketch showing groundwater and water table. Label it.

Rate constant for $n^{th}$ order reaction has dimensions:
(Where M is concentration units)

Large volumes of a gas can be put into a small cylinder and transported easily. The reason behind this is:

Atoms are very small and we cant see it through electric microscope then how we know that there is a thing known as atom

Metals have a property which helps them to be drawn into wires. What is this property of metals known as?

Is ammonium chloride an acidic salt or a basic salt ?

What is the molecular formula for chalk?

Pila globosa is used as biofilter in cleaning pollution of water by:

Who is the inventor of 'Ph' unit?

Which oxide of carbon is harmful and poisonous and are produced on partial burning?

Which of the following gas is responsible for the depletion of Ozone layer?

Why small gaps are left between railway lines?

Scouring is done

Which of the following gas is used as a fire extinguisher?

Explain the steps involved in the production of wool.

Metal bells work on the property called ______.

Which type of soil has the highest water holding capacity?

Magnesium + Cold water ______.

Which amongst the following is the purest form of charcoal?

Answer the following:
a) Liquefied petroleum gas is used in kitchens. When the gas is in a cylinder, it is in the liquid state. When it comes out of the cylinder it becomes a gas (change A), then it burns (change B). Identify the processes A and B.

b) How does the ozone layer in the atmosphere protect us from harmful ultraviolet rays?
[5 MARKS]

Explain an experiment to show that air or oxygen is necessary for combustion. [5 MARKS]

(1)Is setting of curd a chemical change ?Justify the statement

During winter the color of maple leaf changes to bright colors. What do you think about this change?

A reaction : $A_2+B\to$ Products, involves the following mechanism :
$A_2\rightleftharpoons 2A\left(fast\right)$ (A being the intermediate)
$A+B\underset{k_2}{\to }\left(slow\right)$.The rate law consistent to this mechanism is :