Question

1 what is chemistry? (continued)

1. identify three models that scientists use, and explain why each model is useful.
2. evaluate how would your mass and weight differ on the moon? the gravitational force of the moon is one - sixth the gravitational force on earth.
3. evaluate if you put a scale in an elevator and weigh yourself as you ascend and then descend, does the scale have the same reading in both instances? explain your answer.
4. distinguish jacques charles described the direct relationship between temperature and volume of all gases at constant pressure. should this be called charless law or charless theory? explain.

Explanation:

7.

• Physical models: Represent physical objects or systems, like a model of an atom. Useful for visualizing and understanding structure.
• Mathematical models: Use equations and formulas. Help predict behavior of systems, e.g., gas - law equations for predicting gas behavior.
• Conceptual models: Abstract ideas to explain phenomena, such as the kinetic - molecular theory explaining gas properties.

Step1: Define mass and weight concepts

Mass is the amount of matter in an object, a fundamental property that does not change with location. Weight is the force exerted on an object due to gravity, given by $F = mg$, where $m$ is mass and $g$ is gravitational acceleration.

Step2: Analyze mass on the Moon

Since mass is an inherent property of matter, your mass on the Moon is the same as on Earth.

Step3: Analyze weight on the Moon

Let $g_E$ be the gravitational acceleration on Earth and $g_M=\frac{1}{6}g_E$ be the gravitational acceleration on the Moon. If your weight on Earth is $W_E = mg_E$, then your weight on the Moon $W_M=mg_M=m\times\frac{1}{6}g_E=\frac{1}{6}W_E$.

When the elevator is ascending and accelerating upwards, the normal force $N$ (which is the scale reading) is greater than your weight $mg$ because $N - mg=ma$ (Newton's second law, where $a$ is the acceleration of the elevator), so $N = m(g + a)$. When the elevator is descending and accelerating downwards, $mg - N=ma$, so $N=m(g - a)$. When the elevator is moving at a constant speed (either ascending or descending), $a = 0$ and $N = mg$. Since there are acceleration differences in ascending and descending (when accelerating), the scale readings are not the same in all instances.

Answer:

• Physical models: Visualize structure.
• Mathematical models: Predict behavior.
• Conceptual models: Explain phenomena.

8.