Quiz 2: FM:

Describe the main differences between the Rutherford and Bohr models of the atom.

Answer explanation

The Rutherford model depicts the atom as a small, dense nucleus surrounded by orbiting electrons, while the Bohr model introduces quantized orbits for electrons, explaining energy levels and spectral lines.

Create a Plum-Pudding Model.

Which statement best describes the Bohr model of the atom?

• Electrons are located in fixed orbits around the nucleus.

• Electrons are distributed randomly in a cloud around the nucleus.

• Electrons are embedded in a positively charged "soup."

• The atom is mostly empty space with a small dense nucleus.

Answer explanation

The Bohr model describes electrons as being in fixed orbits around the nucleus, which is a key feature distinguishing it from later models that depict electron distribution as a cloud or other forms.

Which atomic theory makes the most sense since the discovery of the neutron?

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Tags

NGSS.HS-PS1-8

What is the primary difference between accuracy and precision?

• Accuracy measures the average; precision measures the range.

• Accuracy is about the number of trials; precision is about the time taken.

• Accuracy is about correctness; precision is about consistency.

• Accuracy refers to the number of attempts; precision refers to the tools used.

Answer explanation

The correct choice highlights that accuracy refers to how close a measurement is to the true value (correctness), while precision indicates how consistent results are when repeated (consistency).

If a set of measurements is very close to each other but not close to the true value, what can be said about the measurements?

• The measurements are neither accurate nor precise.

• The measurements are precise but not accurate.

• The measurements are accurate but not precise.

• The measurements are both accurate and precise.

Answer explanation

The measurements are close to each other, indicating precision, but they are not close to the true value, indicating a lack of accuracy. Therefore, the correct choice is that the measurements are precise but not accurate.

You notice that your laboratory balance consistently measures a known weight as 2 grams more than its true value. What is the likely problem, and how should it be addressed?

Answer explanation

The balance is likely improperly calibrated, consistently adding 2 grams to the measurement. To address this, recalibrate the balance using a known weight to ensure accurate readings.

Why is it necessary to use conversion factors when solving problems involving different units?

• To accurately compare or combine measurements in different units.

• To ensure all measurements are in the same physical dimension.

• To eliminate the need for measurements altogether.

• To simplify calculations without regard to units.

Answer explanation

Using conversion factors is essential to accurately compare or combine measurements in different units, ensuring consistency and correctness in calculations.

Convert 5 liters to milliliters.

• 7500 milliliters

• 2500 milliliters

• 5000 milliliters

• 1000 milliliters

Answer explanation

To convert liters to milliliters, multiply by 1000. Therefore, 5 liters x 1000 = 5000 milliliters. The correct answer is 5000 milliliters.

If a recipe requires 1.5 quarts of milk and you have a measuring jug in liters, how many liters of milk do you need? (1 quart = 0.946 liters)

• 1.5 liters

• 1.2 liters

• 1.8 liters

• 1.42 liters

Answer explanation

To convert 1.5 quarts to liters, multiply by the conversion factor: 1.5 quarts × 0.946 liters/quart = 1.419 liters. Rounding gives approximately 1.42 liters, which is the correct answer.