Use $$\text{Density} = \frac{\text{Mass}}{\text{Volume}}$$; Density = 2.71 g/mL

$$\text{Percent Composition} = \frac{\text{Mass of Element}}{\text{Total Mass of Compound}} \times 100\%$$

Bases decrease the concentration of $$\text{H}^+$$ ions in water.

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

$$\text{Molarity} = \frac{\text{Moles of solute}}{\text{Liters of solution}}$$

$$3.01 \times 10$$^{23}$$ molecules

Question 1

Which of the following best describes the difference between organic and inorganic compounds?

Accepted Answer

Organic compounds are primarily composed of carbon and hydrogen, while inorganic compounds may not contain carbon.

Question 2

A student measures the mass of a sample as 12.34 g and its volume as 4.56 mL. What is the density of the sample, and which formula should be used?

Accepted Answer

Use $$	ext{Density} = \frac{	ext{Mass}}{	ext{Volume}}$$; Density = 2.71 g/mL

Question 3

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

Accepted Answer

Burning of wood

Question 4

A radioactive isotope decays with a half-life of 10 years. If you start with 80 g, how much remains after 30 years?

Accepted Answer

10 g

Question 5

Which of the following best explains why carbon is the backbone of organic molecules?

Accepted Answer

Carbon can form up to four covalent bonds, allowing for complex structures.

Question 6

Which formula correctly represents the calculation for percent composition by mass?

Accepted Answer

$$	ext{Percent Composition} = \frac{	ext{Mass of Element}}{	ext{Total Mass of Compound}} 	imes 100\%$$

Question 7

A patient receives 500 mL of a 0.9% NaCl solution. How many grams of NaCl are in the solution?

Accepted Answer

4.5 g

Question 8

Which of the following statements about acids and bases is correct?

Accepted Answer

Bases decrease the concentration of $$	ext{H}^+$$ ions in water.

Question 9

Which of the following is the correct balanced equation for the combustion of methane ($$	ext{CH}_4$$)?

Accepted Answer

$$	ext{CH}_4 + 2	ext{O}_2 ightarrow 	ext{CO}_2 + 2	ext{H}_2	ext{O}$$

Question 10

A solution has a pH of 3. Which of the following best describes the solution?

Accepted Answer

It is an acidic solution.

Question 11

Which of the following is a correct application of the law of conservation of mass?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 12

Which of the following is the correct formula for calculating molarity?

Accepted Answer

$$	ext{Molarity} = \frac{	ext{Moles of solute}}{	ext{Liters of solution}}$$

Question 13

A sample contains 0.5 moles of glucose ($$	ext{C}_6	ext{H}_{12}	ext{O}_6). $$How many molecules are present?

Accepted Answer

$$3.01 	imes 10$$^{23}$$ molecules

Question 14

Which of the following best describes the role of enzymes in biological systems?

Accepted Answer

Enzymes act as catalysts, speeding up chemical reactions.

Question 15

Which of the following is a correct example of a buffer system in the human body?

Accepted Answer

The $$	ext{H}_2	ext{CO}_3/	ext{HCO}_3^-$$ system in blood

Question 16

A patient is given a medication that must be dissolved in water. Which property of water makes it an excellent solvent for many biological molecules?

Accepted Answer

Water is polar and can form hydrogen bonds.

CHEM1303 General–Organic–Biol Chemistry Syllabus and Course Structure

Guida di studio - Domande di pratica