Is Matter Around Us Pure — Science STD 9 — Question

With the help of an example, explain how diffusion of gases in water is essential?

Show experimentally that matter is made up of small particles.

Which method is better for recovering sugar from sugar solution: evaporation or crystallization? Give reason for your answer.

In photosynthesis, 6 molecules of carbon dioxide combine with an equal number of water molecules through a complex series of reactions to give a molecule of glucose having a molecular formula C₆H₁₂O₆. How many grams of water would be required to produce 18g of glucose? Compute the volume of water so consumed assuming the density of water to be 1g cm^–3.

Calculate the mass of water and mass of glucose required to make 250g of 40% solution of glucose.

Comment upon the following:
Rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and density.

Copper sulphate reacts with sodium hydroxide to form a blue precipitate of copper hydroxide and sodium sulphate. In an experiment, 15.95g of copper sulphate reacted with 8.0g of sodium hydroxide to form 9.75g of copper hydroxide and 14.2g of sodium sulphate. Which law of chemical combination is illustrated by this data? Give reason for your choice.

Why does the temperature remain constant during the boiling of water even though heat is supplied continuously?

Show by an experiment that by increasing the temperature, the substance can be changed into liquid and then into vapours.

Draw a labeled diagram of the experimental set-up to study the latent heat of vaporization of water.