Advertisements
Advertisements
Question
What is meant by (i) elements (ii) compounds, and (iii) mixtures ?Write down the names of two elements, two compounds and two mixtures.
Advertisements
Solution
- Element: An element is a substance that cannot be split up into two or more simpler substances by chemical methods. It contains only one type of atoms. Examples of elements include:
- Non metals: Carbon and oxygen
- Metals: Aluminum, iron, copper, gold, mercury, and lead.
- Compound: A compound is a substance consisting of two or more elements combined chemically in a fixed proportion by mass.
Examples: Water, sodium chloride, calcium carbonate etc. - Mixture: – A mixture is a substance that is made up of two or more different kinds of particles or two or more pure substances mixed together by a physical process. Examples: Air, milk, wood, soil etc.
APPEARS IN
RELATED QUESTIONS
Name the processes involved in two cases.
Fill in the following blank with suitable words :
The best evidence that the particles of matter are constantly moving comes from the studies of ................. and ...................
When a crystal of potassium permanganate is placed in a beaker, its purple colour spreads throughout the water. What does this observation tell us about the nature of potassium permanganate and water?
Explain why air is used to inflate tyres.
What are the characteristics of matter?
What is Brownian motion? Draw a diagram to show the movement of a particle (like a pollen grain during Brownian motion.
Which of the following substances are elements ?
Water, Salt, Mercury, Iron, Marble, Diamond, Wood, Nitrogen, Air, Graphite, Hydrogen, Oxygen, Sugar, Chlorine
What is the name of the clear liquid formed when a solid dissolves in a liquid ?
Choose one term from the following which includes the other three :
aerosol, emulsion, colloid, sol
What is the difference between colloids and suspensions ?
Tincture of iodine has antiseptic properties. This solution is made by dissolving :
How will you separate a mixture containing sand and sugar ?
Describe the method of separating a mixture containing common salt, sand and ammonium chloride.
How will you separate camphor, common salt and iron nails from their mixture ?
Write a few lines on the blackboard with a chalk. Now observe the chalk. What changes do you see in the chalk?
______ is a smallest particle.
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
Which of the following statements are true for pure substances?
(i) Pure substances contain only one kind of particles
(ii) Pure substances may be compounds or mixtures
(iii) Pure substances have the same composition throughout
(iv) Pure substances can be exemplified by all elements other than nickel
Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.
Name a non-metal which exists as a liquid at room temperature.
The most reactive metal is ______.
