a chemical change occurs when
Answer (1)
A chemical change occurs when a substance is transformed into one or more new substances with different chemical properties. This process involves the breaking of existing chemical bonds and the formation of new ones.Here are some common indicators that a chemical change has occurred: * Production of a gas (bubbles): For example, mixing baking soda and vinegar produces carbon dioxide gas. * Formation of a precipitate: This is a solid that forms and separates from a liquid solution, such as when silver nitrate solution is added to sodium chloride solution, forming solid silver chloride. * Change in color: Rusting of iron changes its color from metallic gray to reddish-brown. * Change in temperature: This can be an increase (exothermic reaction, like burning wood) or a decrease (endothermic reaction, like dissolving some salts in water). * Production of light: Many combustion reactions produce light, like a burning candle. * Change in odor: The smell of food decaying is an indication of chemical changes. * Difficulty or impossibility of reversing the change: While some chemical changes can be reversed with further chemical reactions, they generally cannot be undone by simple physical means (like melting ice).In contrast, a physical change alters the form or appearance of a substance but not its chemical composition (e.g., melting ice, cutting paper, dissolving sugar in water).
