Chemistry
Chemistry is the branch of science that deals with the study of matter, its properties, and the changes it undergoes. For the UPSC exam, the focus is not on complex equations but on how chemistry affects our daily lives. Matter around us can undergo two types of changes: physical and chemical. A physical change is a temporary change where no new substance is formed. For example, melting of ice or dissolving sugar in water are physical changes because the original state can be recovered easily.
Concepts (3)
A physical change affects the form of a chemical substance but not its chemical composition. For example, when ice melts into water, it is still H2O. A chemical change occurs through a chemical reaction and creates a new substance.
A physical change affects the form of a chemical substance but not its chemical composition. For example, when ice melts into water, it is still H2O. A chemical change occurs through a chemical reaction and creates a new substance. For example, when milk turns into curd, the lactic acid formed makes it a new substance chemically different from milk.
Carbon exists in different forms called allotropes. In a diamond, each carbon atom is bonded strongly to four others in a rigid shape, leaving no free electrons to move. This makes diamond an insulator.
Carbon exists in different forms called allotropes. In a diamond, each carbon atom is bonded strongly to four others in a rigid shape, leaving no free electrons to move. This makes diamond an insulator. In contrast, graphite has free electrons that allow it to conduct electricity easily. This structural difference is a frequent exam topic.
BPA is an industrial chemical used primarily to make polycarbonate plastics and epoxy resins. Polycarbonate is used in food containers and water bottles. Concerns exist because BPA can mimic hormones in the human body.
BPA is an industrial chemical used primarily to make polycarbonate plastics and epoxy resins. Polycarbonate is used in food containers and water bottles. Concerns exist because BPA can mimic hormones in the human body. UPSC asks about this because it connects chemistry with public health and environmental safety.
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