physical chem. change

• Physical properties include shape, size, color, and state of a substance
• Physical changes are changes in physical properties of a substance, with no new substances formed
• Chemical changes involve the formation of one or more new substances and are generally irreversible
• In a physical change, the physical properties of a substance change, such as shape, size, and state
• In a chemical change, the chemical properties of a substance change
• Rusting is the formation of iron oxide when iron reacts with air and water
• Galvanization is depositing a layer of zinc on iron to prevent rusting, like in galvanized iron pipes
• Painting of an iron gate prevents rusting by blocking contact with air and water
• Rusting of iron objects is faster in coastal areas due to moist air compared to dry air in deserts
• Standard test for carbon dioxide is passing it through lime water, turning it milky with the formation of calcium carbonate
• Crystallization is the process of forming large crystals of pure substances from their saturated solutions