We have read that the sun produces its own heat and light. Is it also some kind of combustion?

A geyser heats water flowing at the rate of 3.0 litres per minute from 27^@ C to 77 ^@C . If the geyser operates on a gas burner. What is the rate of consumption of the fuel if its heat of combustion is 4.0×10 4 J/g?

A cylinder with a movable piston contains 3 moles of hydrogen at standard temperature and pressure. The walls of the cylinder are made of a heat insulator, and the piston is insulated by having a pile of sand on it. By what factor does the pressure of the gas increase if the gas is compressed to half its original volume?

Debate the following issue in class. It is estimated that the sun will last for another five billion years. Do we have to worry about solar energy getting exhausted ? Why or why not ?

The nearest star to our solar system is 4.29 light years away. How much is this distance in terms of parsecs? How much parallax would this star (named Alpha Centauri) show ,when viewed from two locations of the Earth six months apart* in its orbit around the Sun?

A sweet smelling organic compound 'A' is slowly oxidised by air in presence of light to a higly posionous gas. On warming compound A with silver powder, it forms a gaseous substance 'B' which is also produced by the action of calcium carbide on water. identify 'A' and 'B' and write the chemical reactions involved.