problems involving heat flow and temperature changes

Heat and Temperature - Heat energy is present in every object above absolute zero. How do we know that heat is present in every object? Temperature of the body is an indication. (Absolute zero is the lowest temperature possible and is equa..

The flow of information in the living cells involves two mechanisms. One of them is the flow of genetic information contained in the DNA. This information, which is responsible for all cellular activities, is present in the form of a specific sequence of nucleotides an..

A chemical equilibrium involves two opposing reactions. If one of them is exothermic, the other must be endothermic. If a system at equilibrium is subjected to change in temperature, the equilibrium adjusts itself to counteract the effect of the applied change..

This heating is inevitable in any electrical circuit. Since the energy lost by the flowing charges ends up as disorderly thermal motion, the phrase 'ohmic dissipation' is also used to describe it. Often, this is an undesirable effect. For example, in electric circuits, the ..

Action of Heat on Sulphur - When heated, sulphur undergoes a series of characteristic changes. Sulphur can melt at two different temperatures. a) If heated rapidly, it melts at 112.8 o C. b) But if heated slowly it will melt only at 118.6 ..

It has been seen that energy change occurring during the reaction at constant temperature and constant volume is given by internal energy change. However, most of the reactions in the laboratory are carried out in open beakers or test tubes, etc. In such cases, t..

Summary - In a physical change the shape, size, appearance or state of a substance may alter, but it is a temporary change, which is usually reversible. There is no new substance formed, no change in the mass of the substance and no energy changes are in..

Heat flow and Work - Forms of energy transfer First Law of Thermodynamics Law of conservation of energy Thermal energy Distribution of energy levels in a system Entropy of a system Second Law of Thermodynamics Problems involving heat ..

Heat flow and Work - Forms of energy transfer First Law of Thermodynamics Law of conservation of energy Thermal energy Distribution of energy levels in a system Entropy of a system Second Law of Thermodynamics Problems involving heat ..

Introduction - We heat raw food to soften it. We freeze water into ice by cooling it in refrigerator. When we boil water in a kettle we observe the steam oozing from the mouth of the kettle. When the cork is difficult to remove, we slightly heat the mouth of the bottle, so that ..