What are the examples of chemical changes?

What are some examples of chemical and physical changes?

• Answer:

  Physical Changes Change of state (such as from solid to liquid or from gas to liquid) Specific examples of state change include water freezing, alcohol evaporating and dry ice (solid carbon dioxide) subliming Absorption of water into a towel Crumpling a piece of paper Pulling copper into a thin wire - a change of shape, but not a change of composition Cutting a material such as wood Tearing a piece of tin foil Breaking glass Deflating a basketball Mixing different solids (such as solid sulfur and iron filings) Inflating a volleyball Cloud forming in the sky Chemical changes Burning a log of wood Mixing an acid with a base, producing water and a salt. Photosynthesis - a process in which carbon dioxide and water are changed into sugars by plants. Cracking heavy hydrocarbons to create lighter hydrocarbons (part of the process of refining oil). Cooking examples: popcorn, cake, pancakes, and eggs Oxidation examples: rust or tarnishing Combustion Mixing chemicals Rotting of fruit Cooking rice Explosion of fireworks Tarnishing silver Lighting a match Chewing/digesting food Rusting nail Burning gas in a stove Oxidizing food for energy Roasting a marshmallow Adding food coloring to icing Frying an egg Burning a magnesium strip The following can indicate that a chemical change took place, although this evidence is not conclusive: Change of color (for example, silver to reddish-brown when iron rusts) Change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat Change of form (for example, burning paper) Light, heat, or sound is given off Formation of gases, often appearing as bubbles Formation of precipitate (insoluble particles) The decomposition of organic matter (for example, rotting food)