Question 1

A NASA mission failed because engineers used English units instead of SI units for a key calculation. If 1 pound-second equals 4.45 newton-seconds, what is the main lesson for scientists and engineers from this event?

Accepted Answer

Consistent use of SI units and careful unit conversion are critical to avoid costly mistakes.

Question 2

Which of the following is the correct SI base unit for measuring the amount of substance?

Accepted Answer

Mole (mol)

Question 3

A student measures the mass of a penny using a digital balance and records 2.500 g. Which statement best describes the uncertainty in this measurement?

Accepted Answer

The last digit (the thousandths place) is uncertain.

Question 4

Which of the following quantities is an exact number?

Accepted Answer

The number of eggs in a dozen

Question 5

A sample of ethanol has a mass of 15.0 g and a density of 0.798 g/mL. What is the volume of the sample?

Accepted Answer

$$11.8\ \mathrm{mL}$$

Question 6

Which of the following is the correct formula for converting Celsius temperature to Kelvin?

Accepted Answer

$$K = ^\circ C + 273.15$$

Question 7

A graduated cylinder contains 50.0 mL of water. A student adds a metal object, and the water level rises to 62.5 mL. If the mass of the object is 100.0 g, what is its density?

Accepted Answer

$$4.00\ \mathrm{g/mL}$$

Question 8

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

Accepted Answer

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

Question 9

A car travels 28 miles per gallon of gasoline. How many kilometers per liter does it travel? (1 mile = 1.609 km, 1 gallon = 3.785 L)

Accepted Answer

$$7.41\ \mathrm{km/L}$$

Question 10

Which of the following is the correct number of significant figures in the measurement 0.05400?

Accepted Answer

4

Question 11

A scientist adds 2.345 g, 0.07 g, and 2.9975 g. What is the sum, rounded to the correct number of significant figures?

Accepted Answer

$$5.41\ \mathrm{g}$$

Question 12

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

Accepted Answer

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

Question 13

A 10 kg object is dropped from a height and hits the ground, releasing heat. Which type of energy conversion is primarily taking place?

Accepted Answer

Potential energy to kinetic energy and then to heat

Question 14

Which of the following is a derived SI unit?

Accepted Answer

Joule (J)

Question 15

A sample of mercury has a mass of $$1.00 	imes 10^2$ g and occupies a volume of 7.36 cm^3$. What is the density of mercury?

Accepted Answer

$$13.6\ \mathrm{g/cm^3$}$$

Question 16

Which of the following prefixes represents the smallest quantity?

Accepted Answer

Pico-

Question 17

A student needs to convert 8.50 inches to centimeters. Which conversion factor should they use?

Accepted Answer

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

Question 18

Which of the following best describes an exothermic process?

Accepted Answer

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

Question 19

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

Accepted Answer

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

Chapter E: Units, Measurement, and Problem Solving – General Chemistry Essentials

Guida di studio - Domande di pratica

Study guide - Flashcard