Atoms and Molecules — Science STD 9 — Question

How much water should be added to 15 grams of salt to obtain 15 percent salt solution?

Give a brief description of the following: 
Relative atomic mass.

Choose the solutions from among the following mixtures:
Soil, Sea-water, Air, Coal, Soda-water

Name any two elements whose symbols do not start with the same letter as that of the name of the element.

Name a non-metal:
Which is known to form the largest number of compounds.

Is alcohol is a mixture or a pure substance?

Which of the following substances are elements?
Water, Salt, Mercury, Iron, Marble, Diamond, Wood, Nitrogen, Air, Graphite, Hydrogen, Oxygen, Sugar, Chlorine

The molecular formula of glucose is C₆H₁₂O₆. Calculate its molecular mass. (Atomic masses: C = 12 u; H = 1 u; O = 16 u)

Write the chemical formula using criss-cross method:
Ammonium sulphate.

Calculate the mass in grams of 0.17 mole of hydrogen sulphide, H₂S.
(Atomic masses: H = 1u, S = 32u)