Q: Convert $$2.50\ \mathrm{yards} to $$centimeters. (Given: $$1\ \mathrm{yard} = 0.9144\ \mathrm{meters}$$, $$1\ \mathrm{meter} = 100\ \mathrm{cm})$$

$$2.50\ \mathrm{yards} \times 0.9144\ \mathrm{m/yard} \times 100\ \mathrm{cm/m} = 228.6\ \mathrm{cm}$$

Q: Which of the following is the correct relationship for converting Celsius to Fahrenheit?

$$^\circ\mathrm{F} = (^\circ\mathrm{C} \times \frac{9}{5}) + 32$$

Q: A student needs to convert $$3.00\ \mathrm{m}^3 to $$cubic centimeters. Which of the following is the correct conversion factor and result?

$$3.00\ \mathrm{m}^3 \times (1,000,000\ \mathrm{cm}^3/1\ \mathrm{m}^3) = 3.00 \times 10^6$\ \mathrm{cm}^3$$

Question 1

A NASA Mars mission failed because the spacecraft's trajectory corrections were entered in English units instead of metric units. If the on-board computer expected a force in newton-seconds (N·s), but ground engineers provided the value in pound-seconds (lb·s), what is the most likely consequence of this unit mismatch?

Accepted Answer

The spacecraft would receive an incorrect amount of force, potentially causing it to enter the atmosphere at the wrong altitude and disintegrate.

Question 2

Which of the following is the correct SI base unit for temperature, and why is it preferred in scientific measurements?

Accepted Answer

Kelvin (K), because it starts at absolute zero and avoids negative values.

Question 3

A cube has a side length of $$10\ \mathrm{cm}. $$What is its volume in cubic centimeters?

Accepted Answer

$$1000\ \mathrm{cm}^3$$

Question 4

Which of the following statements best describes the difference between mass and weight?

Accepted Answer

Mass is the amount of matter in an object, while weight is the gravitational pull on that matter.

Question 5

A temperature is measured as $$25.0\ ^\circ\mathrm{C}. $$What is this temperature in Kelvin?

Accepted Answer

$$298.2\ \mathrm{K}$$

Question 6

Which of the following is an example of an exact number in scientific measurements?

Accepted Answer

The number of centimeters in a meter ($$100)$$

Question 7

A student measures the mass of a sample as $$8.450\ \mathrm{g}. $$How many significant figures are in this measurement?

Accepted Answer

4

Question 8

Which of the following best describes the law of conservation of energy?

Accepted Answer

Energy can be transferred or transformed, but cannot be created or destroyed.

Question 9

Convert $$2.50\ \mathrm{yards} to $$centimeters. (Given: $$1\ \mathrm{yard} = 0.9144\ \mathrm{meters}$$, $$1\ \mathrm{meter} = 100\ \mathrm{cm})$$

Accepted Answer

$$2.50\ \mathrm{yards} 	imes 0.9144\ \mathrm{m/yard} 	imes 100\ \mathrm{cm/m} = 228.6\ \mathrm{cm}$$

Question 10

A sample of copper has a mass of $$63.5\ \mathrm{g}$$ and a volume of $$7.10\ \mathrm{cm}^3. $$What is its density?

Accepted Answer

$$8.94\ \mathrm{g/cm}^3$$

Question 11

Which of the following measurements contains three significant figures?

Accepted Answer

$$0.0400$$

Question 12

A student records the following measurements for the mass of a sample: $$2.51\ \mathrm{g}$$, $$2.50\ \mathrm{g}$$, $$2.52\ \mathrm{g}$$, and $$2.51\ \mathrm{g}. $$The true mass is $$2.00\ \mathrm{g}. $$Which statement best describes the precision and accuracy of these measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 13

Which of the following is the correct relationship for converting Celsius to Fahrenheit?

Accepted Answer

$$^\circ\mathrm{F} = (^\circ\mathrm{C} 	imes \frac{9}{5}) + 32$$

Question 14

Which SI prefix multiplier corresponds to $$10^{-6}$$?

Accepted Answer

micro

Question 15

A beaker contains $$250.0\ \mathrm{mL} of $$water. Express this volume in liters using the correct number of significant figures.

Accepted Answer

$$0.250\ \mathrm{L}$$

Question 16

Which of the following best describes an exothermic process?

Accepted Answer

A process in which the system releases energy to the surroundings.

Question 17

A student needs to convert $$3.00\ \mathrm{m}^3 to $$cubic centimeters. Which of the following is the correct conversion factor and result?

Accepted Answer

$$3.00\ \mathrm{m}^3 	imes (1,000,000\ \mathrm{cm}^3/1\ \mathrm{m}^3) = 3.00 	imes 10^6$\ \mathrm{cm}^3$$

Question 18

Which of the following is an intensive property?

Accepted Answer

Density

Question 19

A scientist measures a length as $$0.00450\ \mathrm{m}. $$How many significant figures does this measurement have?

Accepted Answer

4

Units, Measurement, and Quantification in General Chemistry

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