C: Heating of Mercuric oxide powder: The heating of Mercuric oxide powder is a permanent change. We cannot get powder by revere reaction so it is a chemical change
Sublimation of Iodine: It is a physical change
Heating a platinum wire in a Bunsen flame: Platinum is a noble gas that cannot change its physical appearance after heating. So it is not a chemical change
Evaporation of Alcohol: It is a physical change. The liquid is changed into gas
The density of water depends on temperature and salt content. Density is measured as mass (g) per unit volume (cc). Water has the highest density at 3.98 ° C and the lowest density at 0 ° C (freezing point).
The electricity we use in our homes is called Alternating Current/ Mains supply.
Alternating current is used in most electricity distribution systems for several reasons, but the most important one is the ease with which it can be transformed from one voltage to another
Mercury is the only metal that is liquid at normal temperatures.
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Chemical compounds of mercury have found uses in batteries, in biocides in the paperindustry, in paints, and on seedgrain, as antiseptics in pharmaceuticals, as reagents in laboratories, and as catalysts.
Four other elements are liquids slightly warmer than room temperature.
