Advertisements
Advertisements
Question
Name the scientist who studied the movement of pollen grains suspended in water through a microscope. What is this phenomenon known as?
Advertisements
Solution
Robert Brown studied the movement of pollen grains suspended in water through a microscope. He observed that the pollen grains moved in a zigzag motion. This phenomenon is called Brownian motion and it provides an evidence for existence and movement of particles.
APPEARS IN
RELATED QUESTIONS
The inter-molecular space is maximum in
Select the correct alternative
The molecules can move freely anywhere in
- gases
- liquids
- solids
- none of the above
What do you mean by the inter-molecular spaces? How do they vary in different states of matter?
Name the processes involved in two cases.
Bromine and air take about 15 minutes to diffuse completely but bromine diffuses into a vacuum very rapidly. Why is this so?
When extremely small particles X derived from the anther of a flower were suspended in a liquid Y and observed through a microscope, it was found that the particles X were moving throughout the liquid Y in a very zig-zag way. It was also observed that warmer the liquid Y, faster the particles X moved on its surface.
- What could particles X be ?
- What do you think liquid Y is ?
- What is the zig-zag movement of X known as ?
- What is causing the zig-zag movement of particles X ?
- Name the scientist who discovered this phenomenon.
- What does this experiment tell us about the nature of liquid Y?
During respiration, glucose and oxygen enter our body cells and waste products carbon dioxide and water leave the body cells by the process of :
Which of the following is a mixture ?
Salt, Air, Water, Alum, Sugar
Name a metal which has no fixed shape.
Draw a flow-chart for the schematic representation of different types of matter.
Iron powder and sulphur powder were mixed together and divided into two parts A and B. When part A was heated strongly over a burner, then a substance C was formed. The part B was, however, not heated at all. When dilute hydrochloric acid was added to substance C, then gas D was evolved and when dilute hydrochloric acid was added to part B then gas E was evolved.
- What type of substance is B ?
- What type of substance is C ?
- Name the gas (i) D, and (ii) E ?
- State one characteristic property of gas D.
- Write one test to identify gas E.
Out of a colloid, solution and a suspension :
which one has the smallest particles ?
Choose the correct answer.
A 5 per cent sugar solution means that :
When the solid A is added to water, it dissolves with the evolution of a lot of heat and making little explosions to form two products B and C. The properties of products B and C are entirely different from those of solid A as well as water. Moreover, products B and C cannot be reconverted into solid A and water. When another solid D is added to water, it dissolves with the absorption of a little heat to form a product E which cools down. The product E shows the properties of both, solid D as well as water. Moreover, product E can be converted into solid D and water.
(a) What type of change occurs when solid A is dissolved in water ? Why ?
(b) What type of change occurs when solid D is dissolved in water ? Why ?
(c) Name a metal which you think could behave like solid A. Also name the products B and C.
(d) Name the solid D if it is the one which is used in making ordinary dry cells.
(e) Name the process by which D can be recovered from E.
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Explain the meaning of the term ‘matter’.
If there is a sudden shower, we take shelter under a roof at the roadside. Even though the rain does not fall on us directly, we get wet to some extent. Why ?
Seema visited a Natural Gas Compressing Unit and found that the gas can be liquefied under specific conditions of temperature and pressure. While sharing her experience with friends she got confused. Help her to identify the correct set of conditions
The pressure of gases does not depend on the temperature of the gas and the volume it occupies.
