Among the options provided, the one that demonstrates a chemical change is:
Iron (Fe) reacting to water (H2O) and oxygen (O) to form iron oxide (Fe2O3).
This is the only option that describes a process where the original substances (iron, water, and oxygen) undergo a chemical reaction to form a new substance with different chemical properties (iron oxide, commonly known as rust). Chemical changes involve the making and breaking of chemical bonds to create new substances.
The other options describe physical changes:
- Sugar and water mixing to create sugar water: This is a physical change because the sugar molecules are simply dispersed in the water and no new substance is created.
- Steam condensing on a mirror: This is a physical change as well, where water vapor (steam) changes physical state from gas to liquid upon contact with a cool mirror surface, but the chemical identity of the water does not change.
- Dry ice vaporizing: Dry ice is solid carbon dioxide (CO2), and its vaporization (sublimation) is also a physical change because the dry ice changes state from solid to gas without altering its chemical composition.
Which of the following demonstrates a chemical change?(1 point)
Responses
sugar and water mixing to create sugar water
iron (Fe) reacting to water(open paren cap h sub 2 cap o close paren) and oxygen(O) to form iron oxide(cap f e sub 2 cap o sub 3)
steam condensing on a mirror
dry ice vaporizing
3 answers
what is the correct answer
The correct answer is:
Iron (Fe) reacting to water (H2O) and oxygen (O) to form iron oxide (Fe2O3).
This is the correct answer because it involves a chemical change where new chemical bonds are formed, resulting in a different substance with new properties. The iron has reacted with water and oxygen to create iron oxide, which is a fundamentally different material than the original iron, water, and oxygen. This is an example of a chemical reaction, specifically corrosion or rusting.
Iron (Fe) reacting to water (H2O) and oxygen (O) to form iron oxide (Fe2O3).
This is the correct answer because it involves a chemical change where new chemical bonds are formed, resulting in a different substance with new properties. The iron has reacted with water and oxygen to create iron oxide, which is a fundamentally different material than the original iron, water, and oxygen. This is an example of a chemical reaction, specifically corrosion or rusting.