Question 1: Classify the following into homogenous and heterogeneous mixtures:
(a) Ice: Homogeneous mixture (since it’s a uniform combination of water molecules in solid form)
(b) Soil: Heterogeneous mixture (since it consists of various components like sand, silt, clay, organic matter, etc., which are not uniformly distributed)
(c) Wood: Heterogeneous mixture (since it contains various components like cellulose, lignin, hemicellulose, etc., arranged in a non-uniform manner)
(d) Air: Homogeneous mixture (since it’s a uniform blend of gases like nitrogen, oxygen, carbon dioxide, etc.)
Question 2: Name the type of mixture formed by mixing sulphur and carbon disulphide:
The type of mixture formed by mixing sulphur and carbon disulphide is a homogeneous mixture.
Question 3: Justify the statement that: ‘Rusting of iron is corrosion and it is a chemical change’:
Rusting of iron involves the chemical reaction between iron, oxygen, and water to form iron oxide (rust). This process is termed as corrosion because it leads to the deterioration of iron due to the formation of a new compound (iron oxide) with different properties. It is a chemical change because the composition of the iron changes as it reacts with oxygen and water to form a new substance (iron oxide), which cannot be easily reversed.
Question 4: Name the processes used for separation:
(a) Miscible liquids: Fractional distillation or Simple distillation
(b) Immiscible liquids: Separatory funnel or Centrifugation
(c) Butter from milk: Centrifugation
(d) Sand from water-sand mix: Filtration
(e) Separation of colors in dyes: Chromatography
(f) Camphor from camphor, sand, and salt: Sublimation
(g) Alcohol from aqueous alcohol: Fractional distillation or Simple distillation
Question 5: Name the apparatus by which a mixture of oil and water can be separated:
The apparatus used to separate a mixture of oil and water is called a separatory funnel or centrifuge.