Q: Which temperature conversion equation is correct for converting Celsius to Kelvin?

$$T(\text{K}) = t(\text{°C}) + 273.15$$

Q: A student records the following measurements: 6.64 cm, 6.68 cm, and 6.70 cm. What is the average, and how many significant figures should it have?

Average: $$6.67 \text{ cm}$$, 3 significant figures

Q: Which of the following is the correct conversion factor to convert inches to centimeters?

$$1 \text{ in} = 2.54 \text{ cm}$$

Q: Which of the following is the correct conversion between calories and joules?

$$1 \text{ cal} = 4.184 \text{ J}$$

Question 1

A NASA spacecraft was lost due to a unit conversion error between metric and English units. If a force was calculated in newtons but entered as pound-seconds, which of the following best explains the consequence of this mistake?

Accepted Answer

The spacecraft's trajectory correction was incorrect, causing it to enter the Martian atmosphere at the wrong altitude.

Question 2

Which of the following is NOT a base unit in the International System of Units (SI)?

Accepted Answer

Liter

Question 3

A student measures the mass of a sample as 0.00801008 g. How many significant figures does this measurement have?

Accepted Answer

6

Question 4

Which of the following numbers has four significant figures?

Accepted Answer

0.01200

Question 5

Convert 105 km/h to meters per second. Use $$1 	ext{ km} = 1000 	ext{ m}$$ and $$1 	ext{ h} = 3600 	ext{ s}.$$

Accepted Answer

$$29.2 	ext{ m/s}$$

Question 6

Which temperature conversion equation is correct for converting Celsius to Kelvin?

Accepted Answer

$$T(	ext{K}) = t(	ext{°C}) + 273.15$$

Question 7

A platinum sample has a density of $$21.5 	ext{ g/cm}^3$$ and a volume of $$4.49 	ext{ cm}^3. $$What is its mass?

Accepted Answer

$$96.5 	ext{ g}$$

Question 8

Which of the following statements about density is TRUE?

Accepted Answer

Density is an intensive property and does not depend on the amount of substance.

Question 9

A student records the following measurements: 6.64 cm, 6.68 cm, and 6.70 cm. What is the average, and how many significant figures should it have?

Accepted Answer

Average: $$6.67 	ext{ cm}$$, 3 significant figures

Question 10

Which of the following is the correct scientific notation for the number 0.0000000000000000000000199?

Accepted Answer

$$1.99 	imes 10$$^{-23}$$

Question 11

A sample of mercury has a density of $$13.6 	ext{ g/cm}^3. $$What is the mass in grams of $$95 	ext{ mL} of $$mercury? (Assume $$1 	ext{ mL} = 1 	ext{ cm}^3)$$

Accepted Answer

$$1292 	ext{ g}$$

Question 12

Which of the following is the correct conversion factor to convert inches to centimeters?

Accepted Answer

$$1 	ext{ in} = 2.54 	ext{ cm}$$

Question 13

Which prefix multiplier corresponds to $$10^{-6} in $$the metric system?

Accepted Answer

micro ($$\mu)$$

Question 14

A student wants to convert $$1516 	ext{ g} to $$kilograms. What is the correct answer?

Accepted Answer

$$1.516 	ext{ kg}$$

Question 15

Which of the following best describes the difference between accuracy and precision?

Accepted Answer

Accuracy is how close a measurement is to the true value; precision is how close repeated measurements are to each other.

Question 16

Which of the following is the correct equation for kinetic energy?

Accepted Answer

$$KE = \frac{1}{2}mv^2$

Question 17

A chemical reaction absorbs heat from its surroundings. Which term best describes this process?

Accepted Answer

Endothermic

Question 18

How many significant figures are in the measurement $$6.030 	imes 10^4$?

Accepted Answer

4

Question 19

Which of the following is the correct conversion between calories and joules?

Accepted Answer

$$1 	ext{ cal} = 4.184 	ext{ J}$$

Essentials of Units, Measurement, and Problem Solving in General Chemistry

Guida di studio - Domande di pratica

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