Q: Perform the following calculation and round to the correct number of significant figures: $$0.0154\ \mathrm{kg} \div 88.3\ \mathrm{mL}$$

$$1.74 \times 10$$^{-4}$$\ \mathrm{kg/mL}$$

Question 1

Which of the following best describes the difference between a scientific law and a scientific theory?

Accepted Answer

A law is a summary of observed phenomena, while a theory is a well-substantiated explanation of those phenomena.

Question 2

A student mixes oil and vinegar in a beaker and observes two separate layers. Which classification best describes this mixture?

Accepted Answer

Heterogeneous mixture

Question 3

Which of the following is a chemical property?

Accepted Answer

Iron rusts in the presence of oxygen.

Question 4

A 15.0 g iron nail reacts with oxygen to form a rusty nail with a mass of 21.4 g. According to the law of conservation of mass, how much oxygen reacted?

Accepted Answer

$$6.4\ \mathrm{g}$$

Question 5

Which of the following is NOT an SI base unit?

Accepted Answer

Liter (L)

Question 6

A student measures the mass of an object three times and records 1.82 g, 1.82 g, and 1.82 g. The true mass is 1.90 g. Which statement is correct?

Accepted Answer

The measurements are precise but not accurate.

Question 7

How many significant figures are in the measurement 0.0044060 kg?

Accepted Answer

5

Question 8

Perform the following calculation and round to the correct number of significant figures: $$0.0154\ \mathrm{kg} \div 88.3\ \mathrm{mL}$$

Accepted Answer

$$1.74 	imes 10$$^{-4}$$\ \mathrm{kg/mL}$$

Question 9

A sample has a mass of 42.15 g and a density of 2.6 g/mL. What is its volume, reported with the correct number of significant figures?

Accepted Answer

$$16\ \mathrm{mL}$$

Question 10

Convert 230 \ ^\circ \mathrm{C} to Fahrenheit.

Accepted Answer

$$446\ ^\circ \mathrm{F}$$

Question 11

Which of the following is a diatomic element you must know?

Accepted Answer

Br$$_2$$

Question 12

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more elements chemically bonded in fixed proportions.

Question 13

A neutral atom of $$^{23}_{11}\mathrm{Na}$$ contains:

Accepted Answer

11 protons, 12 neutrons, 11 electrons

Question 14

Which of the following is the correct symbol for an ion with 20 protons, 20 neutrons, and 18 electrons?

Accepted Answer

$$^{40}_{20}\mathrm{Ca}^{2+}$$

Question 15

Calculate the average atomic mass of copper given 69.17% $$^{63}\mathrm{Cu} (62.9396 $$amu) and 30.83% $$^{65}\mathrm{Cu} (64.9278 $$amu).

Accepted Answer

$$63.55\ \mathrm{amu}$$

Question 16

How many oxygen atoms are in 1 mole of nitrate ions ($$\mathrm{NO}_3^-$$)?

Accepted Answer

$$1.81 	imes 10$$^{24}$$

Question 17

A can of diet soda contains 46 mg of caffeine ($$\mathrm{C}_8\mathrm{H}_{10}\mathrm{N}_4\mathrm{O}_2). $$How many caffeine molecules are in one can? (Molar mass = 194.19 g/mol)

Accepted Answer

$$1.43 	imes 10$$^{20}$$

Question 18

Which of the following is a main group element, a metal, and an alkaline earth metal?

Accepted Answer

Ca

Question 19

Which of the following is the correct conversion factor to convert micrograms ($$\mug) to $$grams (g)?

Accepted Answer

$$1\ \mathrm{g} = 10^6$\ \mu\mathrm{g}$$

General Chemistry Essentials: Matter, Measurement, and Atomic Structure

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