Q: Convert $$2.998 \times 10^8$\ \mathrm{m/s} ($$the speed of light) to $$\mathrm{km/hr}$$. ($$1\ \mathrm{km} = 1000\ \mathrm{m}$$, $$1\ \mathrm{hr} = 3600\ \mathrm{s})$$

$$1.08 \times 10^9$\ \mathrm{km/hr}$$

Question 1

Which of the following best describes an intensive property of matter?

Accepted Answer

It is independent of the amount of substance present.

Question 2

A student measures the mass of a sample as 12.345 g and its volume as 6.7 mL. What is the density of the sample, reported with the correct number of significant figures?

Accepted Answer

$$1.8\ \mathrm{g/mL}$$

Question 3

Which of the following is a chemical change?

Accepted Answer

Burning of gasoline

Question 4

A patient has a cholesterol concentration of $$232\ \mathrm{mg}/100.0\ \mathrm{mL} of $$blood. If the total blood volume is $$5.2\ \mathrm{L}$$, how many grams of cholesterol are in the patient's blood? ($$1\ \mathrm{L} = 1000\ \mathrm{mL}$$, $$1\ \mathrm{g} = 1000\ \mathrm{mg})$$

Accepted Answer

$$12.1\ \mathrm{g}$$

Question 5

Which separation technique would be most appropriate to separate a mixture of ethanol and water?

Accepted Answer

Distillation

Question 6

Which of the following statements about the scientific method is correct?

Accepted Answer

A theory must be consistent with all available data.

Question 7

Which of the following numbers has four significant figures?

Accepted Answer

0.04560

Question 8

Convert $$2.998 	imes 10^8$\ \mathrm{m/s} ($$the speed of light) to $$\mathrm{km/hr}$$. ($$1\ \mathrm{km} = 1000\ \mathrm{m}$$, $$1\ \mathrm{hr} = 3600\ \mathrm{s})$$

Accepted Answer

$$1.08 	imes 10^9$\ \mathrm{km/hr}$$

Question 9

Which of the following is an example of a homogeneous mixture?

Accepted Answer

Salt water

Question 10

A gold-silver alloy weighs $$9.35\ \mathrm{g}$$ and has a volume of $$0.695\ \mathrm{mL}. If $$the densities of gold and silver are $$19.3\ \mathrm{g/mL}$$ and $$10.5\ \mathrm{g/mL}$$ respectively, what is the percentage of gold by mass in the alloy? (Assume total volume is the sum of the volumes of gold and silver.)

Accepted Answer

$$48\%$$

Question 11

Which of the following is NOT a base SI unit?

Accepted Answer

Gram

Question 12

Which of the following best describes a physical property?

Accepted Answer

Boiling point

Question 13

A student needs to convert $$25.0\ \mathrm{cm} to $$feet. Given $$1\ \mathrm{in} = 2.54\ \mathrm{cm}$$ and $$1\ \mathrm{ft} = 12\ \mathrm{in}$$, what is the correct answer with the proper number of significant figures?

Accepted Answer

$$0.82\ \mathrm{ft}$$

Question 14

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

Accepted Answer

Mass

Question 15

Which of the following best explains why the Haber-Bosch process is significant in modern society?

Accepted Answer

It produces ammonia, which is essential for fertilizers and thus global food production.

Question 16

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

Accepted Answer

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

Question 17

A measurement is recorded as $$0.004560\ \mathrm{g}. $$How many significant figures does this value have?

Accepted Answer

5

Question 18

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 19

Which of the following is a correct example of dimensional analysis?

Accepted Answer

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

Question 20

Which of the following best explains why separation techniques such as chromatography were critical to the development of chemistry?

Accepted Answer

They allowed scientists to isolate and identify pure substances from mixtures.

Chemistry 151 Syllabus and Course Information

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