Q: Answer the following question given this paragraph: A: Another example of matter changing color is a penny changing from reddish brown to greenish brown as it becomes tarnished. The color change indicates that a new chemical substance has been produced. Copper on the surface of the penny has combined with oxygen in the air to produce a different substance called copper oxide. Q: What substance is created when a copper turns from reddish brown to greenish brown? Choices: - rust - copper alloy - iron oxide - copper oxide A:
A: copper oxide

Q: Answer the following question given this paragraph: Light is emitted by atoms that have been excited by thermal excitation, electron collision, or collisions with photons of exactly the right frequency. Light is emitted by an incandescent source at many different wavelengths and in all directions. Light produced by an atomic gas consists of only a few different wavelengths but still in all directions. Both of these light sources produce light waves that are not in step or at the same point in their cycle. Groups of light waves that are not at the same point in their cycle are called incoherent light . Q: What is emitted by atoms that have been excited by thermal excitation, electron collision, or collisions with photons of exactly the right frequency? Choices: - electricity - gravity - radioactivity - light A:
A: light

Q: Answer the following question given this paragraph: According to the table, aluminum has an atomic number of 13. Therefore, every aluminum atom has 13 protons in its nucleus. Iron has an atomic number of 26. Therefore, every iron atom has 26 protons in its nucleus. Carbon has an atomic number of 6. Therefore, every carbon atom has 6 protons in its nucleus. Saylor URL: http://www. saylor. org/books. Q: According to the table, aluminum has an atomic number of 13. therefore, every aluminum atom has 13 protons in its what? Choices: - processes - membrane - components - nucleus A:
A: nucleus

Q: Answer the following question given this paragraph: Figure 9.3 This car is in dynamic equilibrium because it is moving at constant velocity. There are horizontal and vertical forces, but the net external force in any direction is zero. The applied force F app between the tires and the road is balanced by air friction, and the weight of the car is supported by the normal forces, here shown to be equal for all four tires. Q: When is a moving car said to be in dynamic equilibrium? Choices: - at rest - at homeostasis - when accelerating - zero net force A:
A: zero net force