$$\frac{\text{mass of O}}{\text{molar mass of } \mathrm{H}_2\mathrm{O}} \times 100\%$$

Question 1

Which of the following statements best describes the difference between an atom and a compound?

Accepted Answer

An atom is the smallest unit of an element, while a compound consists of two or more elements chemically combined.

Question 2

Which equation correctly represents the nuclear decay of Carbon-14 ($$^{14}\mathrm{C}) by $$beta emission?

Accepted Answer

$$^{14}\mathrm{C} \$$rightarrow ^{14}$$\mathrm{N} $$+ ^{0}$$_{-1}\mathrm{e}$$

Question 3

Which of the following best explains why sodium (Na) and chlorine (Cl) form an ionic compound?

Accepted Answer

Sodium donates an electron to chlorine, resulting in oppositely charged ions that attract.

Question 4

Which of the following is the correct formula for calculating the percent composition by mass of oxygen in water ($$\mathrm{H}_2\mathrm{O}$$)?

Accepted Answer

$$\frac{	ext{mass of O}}{	ext{molar mass of } \mathrm{H}_2\mathrm{O}} 	imes 100\%$$

Question 5

A patient receives a radioactive tracer with a half-life of 6 hours. If the initial activity is 80 mCi, what will the activity be after 18 hours?

Accepted Answer

10 mCi

Question 6

Which of the following best describes a carbohydrate?

Accepted Answer

A molecule containing carbon, hydrogen, and oxygen, typically with a 2:1 ratio of hydrogen to oxygen.

Question 7

Which of the following is a balanced chemical equation for the combustion of methane ($$\mathrm{CH}_4$$)?

Accepted Answer

$$\mathrm{CH}_4 + 2\mathrm{O}_2 \rightarrow \mathrm{CO}_2 + 2\mathrm{H}_2\mathrm{O}$$

Question 8

Which of the following best describes the process of stoichiometry in a chemical reaction?

Accepted Answer

Calculating the quantitative relationships between reactants and products using balanced equations.

Question 9

Which of the following is a correct Lewis structure for water ($$\mathrm{H}_2\mathrm{O}$$)?

Accepted Answer

O atom with two single bonds to H atoms and two lone pairs on O

Question 10

Which of the following best explains why organic chemistry is important in medicine?

Accepted Answer

Organic chemistry studies carbon-containing compounds, which form the basis of most drugs and biomolecules.

Question 11

A sample contains 0.5 mol of glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6). $$What is its mass? (Molar mass of glucose = 180 g/mol)

Accepted Answer

90 g

Question 12

Which of the following is a correct example of a chemical reaction?

Accepted Answer

$$2\mathrm{H}_2 + \mathrm{O}_2 \rightarrow 2\mathrm{H}_2\mathrm{O}$$

Question 13

Which of the following best describes the difference between a covalent and an ionic bond?

Accepted Answer

Covalent bonds involve sharing electrons, while ionic bonds involve the transfer of electrons.

Question 14

Which of the following is the correct empirical formula for glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$$)?

Accepted Answer

$$\mathrm{CH}_2\mathrm{O}$$

Question 15

A radioactive isotope decays with a half-life of 2 days. If you start with 32 g, how much remains after 6 days?

Accepted Answer

4 g

Question 16

Which of the following best describes the role of stoichiometry in pharmaceutical manufacturing?

Accepted Answer

It ensures the correct proportions of reactants are used to maximize yield and minimize waste.

Course Schedule: Atoms, Compounds, and Chemical Reactions (Syllabus Excerpt)

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