Which two sentences taken together provide the best evidence to support the ideas that both physical and chemical change can significantly change the appearance of a substance ? A. in a physical change the material involved is structurally the same before and after the change

B. a piece of metal may be heated in a fire until it glows but the metal is the same material before Heating and after Cooling

C. chemical changes require the breaking and forming of chemical bonds during a chemical reaction

D. the creation of a new ,solid substance from to liquid substance into the kids that a reaction has taken place that has alerted the original substance

Achemical reaction (also known as a chemical change) produces substances that are chemically different from the starting materials. an example of a chemical reaction is the formation of water from hydrogen and oxygen gas. in a physical change, a substance changes its physical appearance but not its chemical identity. an example of physical change is the formation of liquid water from solid water, a familiar process called melting. physically, liquid water looks very different from solid water (ice) but the chemical identity, water, is the same for both. which of following changes that affect the composition of our atmosphere involve physical changes and which involve chemical reactions? oxygen gas changes to ozone during thunderstorms carbon dioxide is produced by the combustion of gasoline in an automobile engine. when coal, oil, and natural gas are decomposed in landsills they produce methane gas. freezing rain develops when a warm air mass overrides a cold air mass. fog forms from water vapor when the temperature drops below the dew point

Frictional forces acting on an object are often converted into energy, which causes the temperature of the object to rise slightly.

Suppose a lab group reports a ppercent yield of sand of 105. is it really possible to collect more sand than was originally represented? what is the possible explanation for the extra product?