Q: A student measures the density of magnesium as 1.89 g/mL. The accepted value is 1.74 g/mL. What is the percent error associated with the student's measurement?

$$\frac{1.89 - 1.74}{1.74} \times 100 = 8.6\%$$

Q: Which of the following conversion factor sequences for units would effect the change from ft/sec to km/hr?

$$\frac{1\,\text{ft}}{1\,\text{sec}} \times \frac{12\,\text{in}}{1\,\text{ft}} \times \frac{2.54\,\text{cm}}{1\,\text{in}} \times \frac{1\,\text{m}}{100\,\text{cm}} \times \frac{1\,\text{km}}{1000\,\text{m}} \times \frac{3600\,\text{sec}}{1\,\text{hr}}$$

Q: The average adult has approximately 9.0 pints of blood. If 20 drops of blood is equivalent to 1 mL, how many drops of blood does the average human contain? (1 pint = 473 mL)

$$9.0 \times 473 \times 20 = 85,140$$ drops

Q: If the temperature increases by 20$$^\circC on $$the Celsius scale, how many degrees will it rise on the Fahrenheit scale?

$$20 \times \frac{9}{5} = 36^\circF$$

Question 1

Which of the following best describes the difference between physical chemistry and organic chemistry?

Accepted Answer

Physical chemistry studies the properties and behavior of matter, while organic chemistry focuses on compounds containing carbon.

Question 2

A student measures the density of magnesium as 1.89 g/mL. The accepted value is 1.74 g/mL. What is the percent error associated with the student's measurement?

Accepted Answer

$$\frac{1.89 - 1.74}{1.74} 	imes 100 = 8.6\%$$

Question 3

Which of the following is a hypothesis?

Accepted Answer

A tentative model or statement that offers an explanation for a scientific law.

Question 4

A technician measures the pH of a blood sample three times and gets 6.88, 6.89, and 6.98. The actual pH is 7.40. How would you describe the technician's performance?

Accepted Answer

Precise but not accurate

Question 5

Which of the following contains three significant figures, and no others?

Accepted Answer

1.36 	imes $$10^2$$

Question 6

Express the following calculation to the proper number of significant figures: $$\frac{126 	imes 1.364}{135 	imes 0.989}$$

Accepted Answer

1.42

Question 7

Which of the following is the metric system prefix incorrectly paired with a power of ten?

Accepted Answer

hecto - $$10^3$$

Question 8

Which of the following are the correct units for volume?

Accepted Answer

cm$$^3$$

Question 9

Which of the following conversion factor sequences for units would effect the change from ft/sec to km/hr?

Accepted Answer

$$\frac{1\,	ext{ft}}{1\,	ext{sec}} 	imes \frac{12\,	ext{in}}{1\,	ext{ft}} 	imes \frac{2.54\,	ext{cm}}{1\,	ext{in}} 	imes \frac{1\,	ext{m}}{100\,	ext{cm}} 	imes \frac{1\,	ext{km}}{1000\,	ext{m}} 	imes \frac{3600\,	ext{sec}}{1\,	ext{hr}}$$

Question 10

The average adult has approximately 9.0 pints of blood. If 20 drops of blood is equivalent to 1 mL, how many drops of blood does the average human contain? (1 pint = 473 mL)

Accepted Answer

$$9.0 	imes 473 	imes 20 = 85,140$$ drops

Question 11

Density is an easy way to distinguish between gold (density: approx. 19 g/cm$$^3) $$and fool's gold (density: approx. 4.5 g/cm$$^3). If a $$large golden rock has a mass of 252 g and a volume of 56 cm$$^3$$, what type of mineral is it?

Accepted Answer

Fool's gold

Question 12

If the temperature increases by 20$$^\circC on $$the Celsius scale, how many degrees will it rise on the Fahrenheit scale?

Accepted Answer

$$20 	imes \frac{9}{5} = 36^\circF$$

Question 13

The surface temperature of the sun is 7530$$^\circC. $$What is the surface temperature of the sun in degrees Kelvin?

Accepted Answer

$$7530 + 273 = 7803 K$$

Question 14

Which of the following element/chemical symbol pairs is incorrectly matched?

Accepted Answer

Chromium - Cu

Question 15

Which of the following statements concerning the known elements is true?

Accepted Answer

81 of the elements are naturally occurring.

Question 16

Which of the following best describes a chemical change?

Accepted Answer

Hydrochloric acid is added to baking soda resulting in the evolution of carbon dioxide gas.

Question 17

A pure substance A is found to decompose upon heating into two new, pure substances, B and C. A = B + C. Neither B nor C can be decomposed by chemical means. From this we may conclude that:

Accepted Answer

A is a compound, and B and C are elements.

Question 18

Which of the following is an example of an extensive property?

Accepted Answer

Volume

Introduction to Chemistry: Key Concepts and Practice Questions

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