Lakhmir Singh & Manjit Kaur (Chemistry-2020, 2021) - GeniusJnr

How was an iron plough better than that of wood?

Why do some parts of India experience floods and droughts at the same time?

In the following set of substances, one item does not belong to the set. Select this item and explain why it does not belong to the set :
Hydrogen, Oxygen, Steam, Chlorine

In general, cell sizes are not related to the size of an organism. However, will there be a difference in the length of the nerve cells in a rat and a giraffe?

In a village, farmers started cultivating crops all around a lake which was always filled with water. They added lot of materials W to the soil in their fields to increase the yield of crops. Soon they found that the whole surface of water in the lake was covered with a green layer made up of tiny organisms X. After some time, the fish present in the lake started dying in large numbers because they could not get sufficient Y due to a process Z which had occurred in lake water and drained out all the Y present in the water of lake.
(a) What do you think materials W are?
(b) Name (i) X, and (ii) Y.
(c) What is the process Z known as?
(d) What happens during the process Z which uses up all the Y present in lake water?
(e) What does this example tell us about the use of materials like W?

Copy the figure given below which shows a plotting compass and a magnet. Label the N pole of the magnet and draw field line on which the compass lines.

When a piece of limestone reacts with dilute HCl, a gas X is produced. When gas X is passed through lime water then a white precipitate Y is formed. On passing excess of gas X, the white precipitate dissolves forming a soluble compound Z.
(a) What are X, Y and Z?
(b) Write equations for the reactions which take place:
(i) when limestone reacts with dilute HCl
(ii) when gas X reacts with lime water to form white precipitate Y
(iii) when excess of gas X dissolves white precipitate Y to form a soluble compound Z

Define accounting.

What are the objectives of preparing financial statements?

State the meaning of incomplete records?

What is public company?