Environmental Management — Science STD 9 — Question

Take small samples of sugar, wool, dry leaves, hair, seeds, split pulses and plastic in separate test tubes. Heat each test tube and observe the changes taking place in the substances. What does the black substance in each test tube indicate?

Explain the need for a reference atom for atomic mass. Give some information about two reference atoms.

Argon gas is filled in two identical bottles X and Y. The mass of the gas in the two bottles is 5 gm and 25gm respectively. If the speed of sound is the same in both bottles, what conclusions will you draw?

(1) Village Industries Planning Committee – Development of Industries in rural areas
(2) Vidya Niketan – residential highschools
(3) Rural water supply schemes – sinking wells
(4) Objective of Sixth Five Year Plan – Advanced technology(Write the wrong pair)

Into which two categories can the waste materials in the lists above be classified ?

Explain with examples what is meant by a ‘mole’ of a substance.

Ethanol is produced by the fermentation of molasses.

Write the formula : Work

How is excretion in plants useful to human beings?

Take some milk in an evaporating dish. Heat the evaporating dish on a bunsen burner. What remains behind at the bottom of an evaporating dish on complete evaporation of the milk?