During an investigation, students dropped a tarnished penny into a solution of acetic acid and sodium chloride. Tiny bubbles for
med around the penny, and the penny was less tarnished after two minutes of soaking in the acetic acid and sodium chloride solution. The student inferred that a chemical reaction occurred. What evidence supports the student’s inference?
The penny experienced a color change, and a gas was produced.
The penny experienced a color change, and a precipitate was formed.
The penny experienced a color change and is in a new state of matter.
The penny experienced a color change and produced light.
Combining the two clear colorless liquids is a chemical change because a different solid substance is formed. Tell students that a precipitate is an insoluble solid that forms when two solutions are combined and react chemically. Insoluble means that the solid will not dissolve.
The Earth is divided into two halves by the prime meridian, forming two half spheres divided vertically. The Earth is also divided into two halves by the equator, creating two half spheres divided horizontally.