What is the general name of the materials which contain at least two pure substances and show the properties of the constituents?
“The properties of the product are different from those of the constituents”. State whether this statement best describes an element, a compound or a mixture.
What name is given to those elements which are neither good conductors of electricity like copper nor insulators like sulphur?
Fill in the following blanks with suitable words:
(a) An element is made up of only one kind of _________.
Classify the following as elements or compound:
Iron, Iron sulphide, Sulphur, Chalk, Washing soda, Sodium, Carbon, Urea
Which of the following are ‘pure substances’?
Ice, Milk, Iron, Hydrochloric acid, Calcium oxide, Mercury, Brick, Wood, Air
Explain why, hydrogen and oxygen are considered elements whereas water is not considered an element.
What are the three groups into which all the elements can be divided? Name two elements belonging to each group.
Which of the following substances are elements?
Water, Salt, Mercury, Iron, Marble, Diamond, Wood, Nitrogen, Air, Graphite, Hydrogen, Oxygen, Sugar, Chlorine
Compare the properties of metals and non- metals with respect to (i) malleability (ii) ductility, and (iii) electrical conductivity.
State one property in which a solution of sugar in water resembles a mixture of sugar and sand, and one property in which it differs from it.
You are given two liquids, one a solution and the other a compound. How will you distinguish the solution from the compound?
Name a non-metal:
(c) Whose one of the allotropic forms is a good conductor of electricity. Name the allotrope.
Which of the following are not compounds?
Chlorine gas, potassium chloride, Iron powder, Iron sulphide, Aluminium foil, Iodine vapour, Graphite, Carbon monoxide, Sulphur powder, Diamond
(b) Classify the following materials as homogeneous mixtures and heterogeneous mixtures.
Soda-water, Wood, Air, Soil, Vinegar, Alcohol and water mixture, Petrol and water mixture, Chalk and water mixture, Sugar and water mixture, Copper sulphate solution.
(a) What is meant by (i) elements (ii) compound, and (iii) mixtures? Write down the names of two elements, two compounds and two mixtures.
(b) Classify the flowing into elements , compounds and mixtures:
Marble, Air, Gold, Brass, Sand, Diamond, Graphite, Petroleum, Common salt, Sea-water, Chalk
(a) What are (i) metals (ii) non-metals, and (iii) metalloids? Give two examples each of metal, non-metals and metalloids.
(b) Classify the following into metals, non-metals and metalloids:
Silicon, Mercury, Diamond, Sulphur, Iodine, Germanium, Sodium, Carbon, Magnesium, Copper, Boron, Helium
(b) What is meant by (i) homogeneous mixtures, and (ii) Heterogeneous mixtures? Give two examples of homogeneous mixtures and two of heterogenous mixtures.
Which of the following are compounds?
(i) CO (ii) No (iii) NO (iv) Co
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (ii) and (iv)
One of the following substances is neither good conductor of electricity nor an insulator. This substance is:
The element which is not common between the compounds called baking soda and soda ash is:
The elements which normally exist in the liquid state are:
(a) Bromine and Iodine
(b) Mercury and chlorine
(c) Iodine and mercury
(d) Bromine and mercury
The property/properties which enable copper metal to be used for making electric wires is/are:
(a) Copper metal is malleable and ductile
(b) Copper metal is good conductor of electricity
(c) Copper metal is ductile and has low electrical resistance
(d) Copper metal is sonorous and an excellent conductor of electricity
On the basis of composition of matter, milk is considered to be:
(a) A pure substance
(b) An impure substances
(c) An element
(d) A compound
Which of the following statement 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
(a) (i) and (ii)
(b) (i) and (iii)
(c) (iii) and (iv)
(d) (ii) and (iii)
Two chemical substance X and Y combine together to form a product P which contains X and Y
X + Y → P
X and Y cannot be broken down into simpler substance by simple chemical reactions. Which of the following statements concerning X, Y and P are correct?
(i) P is a compound
(ii) X and Y are compounds
(iii) X and Y are elements
(iv) P has a fixed composition
(a) (i), (ii) and (iii)
(b) (i), (ii) and (iv)
(c) (ii), (iii) and (iv)
(d) (i), (iii) and (iv)
Which of the following does not have a fixed melting point/boiling point?
When a mixture of iron powder and sulphur powder is heated strongly to form iron sulphide, then heat energy is:
(b) First absorbed and then released
(d) Neither absorbed nor released
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