☰
Atoms And Molecules
How did Robert Boyle prove experimentally that in vacuum, all bodies fall at the same rate?
Boyle's experiment:
Fig. Boyle's experiment of coin and paper (a) in vacuum, (b) in air.
i) Robert Boyle took a long glass tube, a heavy coin and a piece of paper were placed inside it as shown in the Fig. below
ii) The ends of the tube were closed and air of the tube was removed by a vacuum pump.
iii) When the tube was quickly inverted, it was observed that both the coin and the paper hit the bottom at the same time.
iv) On repeating the experiment with air inside the tube, it was observed that the piece of paper falls slowly while the coin hits the bottom immediately.
v) thus, Galileo's assertion was proved, that in vacuum all bodies irrespective of their mass fall towards the earth with the same acceleration.
Sponsor Area
Give the names of the elements in the following compounds.
(a) Quick lime
(b) Hydrogen bromide
(c) Baking powder
(d) Potassium sulphate.
Calculate the molar mass of the following substances:
(a) Ethylene
(b) Sulphur molecule, S8
(c) Phosphorus molecule, P4
(d) Hydrochloric acid, HCl
(e) Nitric acid, HNO3.
What is the mass of:
(a) 1 mole of nitrogen atoms
(b) 4 moles of aluminium atoms
(c) 10 moles of sodium sulphite.
Convert into mole
(a) 12 gm of oxygen gas
(b) 20 gm of water
(c) 22 gm of carbon dioxide.
What is the mass of?
(a) 0.2 mole oxygen atoms.
(b) 0.5 mole of water molecules.
Calculate the number of molecules of sulphur (S8) present in 16 gm of solid sulphur.
Calculate the number of aluminium ions present in 0.56 gm of aluminium oxide.
Explain law of conservation of mass.
50 g of 10% lead nitrate is mixed with 50 g of 10% sodium chloride in a closed vessel. After the reaction has taken place, it was found that 6.83 g of lead chloride was precipitated. Besides, the reaction mixture contained 90 g water and sodium nitrate. Calculate the amount of sodium nitrate formed.
Name and explain two important laws of chemical combination ?
Sponsor Area
Sponsor Area