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We will get very tiny particles of chalk.

The molecules of perfume move out of the bottle and collide with other molecules in the air and eventually perfume spreads throughout the room.

The cloth will absorb the ink drop and cloth will have a stain mark on it.

A pure substance consists of only one kind of matter, that is. all the particles are same. It has a definite composition and constant properties. It cannot be split into simpler substances by physical metal pure substances have characteristic melting and boiling points. A pure substance is either a compound or an element. 

A mixture contains two or more substances in any proportion which can be separated by physical methods. Mixtures are generally of two types: Homogeneous and Heterogeneous. In a mixture, the constituents can be present in any ratio. They do not have characteristic melting and boiling points. In a mixture, each constituent retains its original properties. These can be separated by physical means.

Alum the substance you will add to speed up sedimentation.

Fractional distillation is used to separate liquids having an appreciable difference in their boiling points.

a variable ratio

True

A separating funnel can be used for separating a mixture of immiscible liquids.

1. A pure substance has only one kind of matter.

2. The composition and properties of a homogenous mixture is uniform throughout.

3. An alloy is a homogeneous mixture of two or more metals.

4. Chalk powder dissolved in water is an example of a suspension.

5. An emulsion is formed when one liquid is dispersed as tiny droplets throughout another liquid.

6. Immiscible liquids are separated by using a separating funnel.

impurities become heavy and sink to the bottom.

1. A pure substance has only one kind of matter.

2. The composition and properties of a homogenous mixture is uniform throughout.

3. An alloy is a homogeneous mixture of two or more metals.

4. Chalk powder dissolved in water is an example of a Chalk powder dissolved in water is an example of a suspension.

5. An emulsion is formed when one liquid is dispersed as tiny droplets throughout another liquid

6. Immiscible liquids are separated by using a separating funnel.

Winnowing is the method used to separate chaff from grain.

True

Milk is an emulsion.

Oil and water, lemon juice and sherbet, bhel, honey and tea, milk and chocolate, coffee and cream, salt and water, smog (smoke + fog) air (oxygen + nitrogen), salad, milk.

False. 

The constituents of a mixture can be separated by chemical means and physical means.

Nearly all of the earth’s atmosphere is made up of gases → Nitrogen, Oxygen, Carbon dioxide, Argon and Neon, Helium and Krypton.

Properties of elements are due to molecules present in it. The molecules are made of one or more atoms which are exactly alike. The mass and volume of atoms of different elements are different.

Mixtures are basically of two types:

(i) Homogeneous 

(ii) Heterogeneous

Homogeneous Mixtures: The composition of these mixtures is uniform throughout the mixture. Besides the properties of the mixture are the same in all the parts of the mixture, e.g. sugar dissolved in water.

Heterogeneous Mixtures: A heterogeneous mixture composition is not uniform throughout the mixture. The properties of the mixture are different in different parts of mixture e.g. chalk dissolved in water.

i. Solid, liquid, gaseous

ii. solid

iii. liquid

iv. freezing point

v. matter

vi. Gas

vii. volume

viii. solid

ix. expand

x. mixture

Supernatant liquid and Fill rate

Supernatant liquid

1. It is obtained during sedimentation.

2. It is used to separate the mixture of liquid and insoluble solid heavier than liquid.

3. No filter paper is used.

Filt rate

1. It is obtained during filtration.

2. It is used to separate fine particles of insoluble solids from liquids.

3. filter paper is used.

Iron sulphide is a compound which can be broken into the elements iron and sulphur they both have different properties. The properties of compound are entirely different from there of its constituents elements.

(a) Solid-solid homogenous mixture — Alloys of metals e.g. brass, bronze stainless steel etc.

(b) Solid-liquid heterogenous mixture — Sand and water, mud and water, sugar and oil.

(c) Miscible liquids — water and ethanol.

(d) Liquid-gas homogenous mixture — Air

1. In water Hydrogen and Oxygen combine chemically in the ratio of 2:1

2. Air is a mixture of many gases.

No, carbon dioxide is a compound. A molecule of the compound CO₂ contains one atom of the element carbon and two atoms of the element oxygen.

1. Water is formed by a combination of hydrogen and oxygen but does not help combustion.

2. It is used to extinguish a fire.

Oxygen helps combustion.

1. Elements: An element is the basic form of matter that cannot be broken down into simpler substances by chemical reactions.

2. Compounds: A compound is a pure substance formed by the chemical combination of two or more elements in a fixed ratio by mass.

The properties of sodium chloride are completely different from those of sodium and chlorine. Sodium is a soft, highly reactive metal. Chlorine is a poisonous non-metallic gas while sodium chloride is a very useful non-poisonous compound which is added to our food to get minerals and also to add taste to it.

Loading is basically speeding up sedimentation.

Pure substance: Pure substances have a definite set of properties such as boiling point, melting point, density, etc. They are all homogeneous i.e., their composition is uniform throughout the bulk. Both elements and compounds are pure substances.

Pure substances are needed to :

1. Manufacture medicines.

2. To prepare chemicals in industry.

3. For scientific purposes.

4. To maintain the good health of human beings.

Filtration is a method used to separate fine particles of insoluble solid from a liquid.

Sedimentation and Decantation

Loading is basically speeding up sedimentation.

Yes, metals are elements.

(a) Gold

(b) Zinc

(c) Iodine

(d) Mercury

(e) Tungsten

(f) Graphite

(g) Bromine

(h) Diamond

(i) Neon, helium

(a) Elements: Element is a substance which cannot be broken further into simpler substances and has a definite set of properties. Elements are made up of only one kind of atoms.

(b) Compounds: Compounds are pure substances composed of two or more elements in definite proportion by mass and have properties, entirely different from those of its constituents elements.

Compound, are made up of different types of atoms combined chemically.

1. A pure substance has definite composition and constant properties.

2. Mixtures can be heterogeneous or homogenous.

3. Use of a sieve to separate the components of a mixture of solids is based on the difference in the size of the components.

4. Winnowing is used when the constituents of a mixture of solids have a difference in their weights.

5. Iodine, camphor, naphthalene, ammonium chloride, and dry ice are some substances that sublimate.

Filtration is a method used to separate fine particles of insoluble solid from a liquid.

True

All pure substances have characteristic melting and boiling points.

(a) Metals: Iron, silver, gold.

(b) Non-metals: Carbon, sulphur, oxygen.

(c) Metalloids: Antimony, silicon, boron.

(d) Inert gases: Helium, argon, neon.

(a) Sodium bicarbonate (Baking soda) — NaHCO₃

(b) Acetic acid (Vinegar) — CH₃COOH

(c) Calcium carbonate (Marble) — CaCO₃

(d) Silicon dioxide (Sand) — SiO₂

1.True

2.True

3.False. 

Correct: A heterogeneous mixture has a non-uniform composition through the mixture.

4.False. 

Correct: The constituents of a mixture can be separated by chemical means and physical means.

5. False. 

Correct: Handpicking can be used as a separation technique if the particle size of the constituents of the mixture is the not the same.

1. A pure substance has definite composition and constant properties.

2. Mixtures can be heterogeneous or homogenous.

3. Use of a sieve to separate the components of a mixture of solids is based on the difference in the size of the components.

4. Winnowing is used when the constituents of a mixture of solids have difference in their weights.

5. Iodine, camphor, naphthalene, ammonium chloride, and dry ice are some substances that sublimate.

Elements are those substances which cannot be subdivided chemically or cannot be synthesized out of other elements.

Correct answer is b. Mixture

(a) Pure substances — 

1. Pure substances have definite composition and definite physical and chemical properties. 

2. They are all homogeneous i.e. their composition is uniform throughout the bulk. 

3. Examples: Elements and compounds. 

Impure substances — 

1. Impure substances are made up of two or more pure substances mixed together in any proportion. 

2. They may be homogeneous or heterogeneous i.e. their composition is not uniform throughout the bulk. 

3. They are all mixtures. 

Examples: air, sea water, petroleum, a solution of sugar in water are all impure substances.

(b) Homogeneous mixture — is a mixture where the components that make up the mixture are uniformly distributed throughout the mixture. 

Example — air, sugar water, rainwater. 

Heterogeneous mixture — is a mixture, where the components of the mixture are not uniform or have localized regions with different properties. 

Example—Cereal in milk, vegetable soup.

2. Helium is an example for gaseous form.

2. The molecular formula of water is H₂O

1. Oxygen is an example for element

2. Water contains hydrogen and oxygen in the ratio of 2:1.