Advertisements
Advertisements
प्रश्न
Explain why, hydrogen and oxygen are considered elements whereas water is not considered an element.
Advertisements
उत्तर
Hydrogen and oxygen are considered as elements because they cannot be split further into simpler substances by usual chemical methods as they are made of one kind of atoms. On the other hand, water is not an element, as it consists of different types of atoms, i.e., hydrogen and oxygen and can be split up into its components by chemical processes.
APPEARS IN
संबंधित प्रश्न
Differentiate between an atom and a molecule.
Which one is a kind of matter:
Explain why steel is used to make railway lines.
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 are ‘pure substances’ ?
Ice, Milk, Iron, Hydrochloric acid, Calcium oxide, Mercury, Brick, Wood, Air
You are given two liquids, one a solution and the other a compound. How will you distinguish the solution from the compound ?
Which of the following is not an element ?
A, B and C are all liquids. Liquid A has a comparatively low boiling point. On heating, liquid A vaporises completely without leaving behind any residue. Liquid A is being used increasingly as a fuel in motor vehicles either alone or by mixing with petrol. Liquid B has a very high boiling point. It also vaporises completely on heating, without leaving any residue. Liquid B is a conductor of electricity and used in making thermometers. Liquid C has a moderate boiling point. On heating, liquid C vaporises leaving behind a white solid D which is used in cooking vegetables. The condensation of vapours from C give a liquid E which turns anhydrous CuSO4 to blue.
(a) Which liquid could be an element ? Name this element.
(b) Which liquid could be a mixture ? Name this mixture.
(c) Which liquid could be a compound ? Name this compound.
(d) What could the solid D be ?
(e) What do you think is liquid E ?
A solution contains 5.6 mL of alcohol mixed with 75 mL of water. Calculate the concentration of this solution.
The solubility of ammonium chloride in water at various temperatures is given below :
| Temperature | : | 10°C | 20°C | 40°C | 60°C | 80°C |
| Solubility | : | 24 g | 37 g | 41 g | 55 g | 66 g |
What mass of ammonium chloride would be needed to make a saturated solution of ammonium chloride in fifty grams of water at 40°C ?
State whether the following statement are true or false :
Alcohol can be separated from a mixture of alcohol and water by a separating funnel.
State whether the following statement are true or false :
Salt and water can be recovered from an aqueous salt solution by the process of evaporation.
Fill in the following blanks with suitable words :
The separation of liquids by fractional distillation is based on the difference in their .....................
Describe a method for separating a mixture of iron filings and sulphur powder other than that by using a magnet.
The technique which is used to separate particles of a solid suspended in a liquid quickly is called :
Which of the following cannot be separated from air by the process of fractional distillation ?
The given mixture contains three constituents A, B and C. The constituent A is a yellow coloured, solid element which dissolves in a liquid D. The constituent B is a blue coloured salt which is insoluble in liquid D but dissolves easily in another liquid E. The constitudent C is a liquid which is used in cooking food and forms a solid fat on hydrogenation.
(a) What do you think could (i) constituent A, and (ii) liquid D be ?
(b) What could (i) constituent B, and (ii) liquid E be ?
(c) What could liquid C be ?
(d) How will you separate the mixture containing A, B and C ?
Give some examples of the Tyndall effect observed in your surroundings?
Solid is an arrangement of particles ______.
Define the term matter.
