Question 1

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout.

Question 2

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

Accepted Answer

$$Density = \frac{Mass}{Volume}$$

Question 3

A student measures the mass of a sample as 12.5 g and its volume as 5.0 mL. What is the density of the sample?

Accepted Answer

$$2.5\ \mathrm{g/mL}$$

Question 4

Which of the following changes is a chemical change?

Accepted Answer

Iron rusting in the presence of oxygen.

Question 5

Which metric prefix represents $$10^{-3}$$?

Accepted Answer

milli-

Question 6

Convert 250 mL to liters using the correct metric conversion.

Accepted Answer

$$0.250\ \mathrm{L}$$

Question 7

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 8

What is the molar mass of water ($$H_2O$$)?

Accepted Answer

$$18.02\ \mathrm{g/mol}$$

Question 9

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their valence shell.

Question 10

Which of the following is a correct Lewis structure for methane ($$CH_4$$)?

Accepted Answer

A central carbon atom with four single bonds to four hydrogen atoms.

Question 11

Which of the following molecules is polar?

Accepted Answer

Water ($$H_2O)$$

Question 12

What is the value of Avogadro's number?

Accepted Answer

$$6.022 	imes 10$$^{23}$$

Question 13

Which of the following is a saturated lipid?

Accepted Answer

A lipid with only single bonds between carbon atoms.

Question 14

Which type of reaction involves breaking a compound into simpler substances?

Accepted Answer

Decomposition reaction

Question 15

Which of the following intermolecular forces is the strongest?

Accepted Answer

Ionic attraction

Question 16

Which of the following best describes an amphipathic compound?

Accepted Answer

A compound with both hydrophilic and hydrophobic regions.

Question 17

Which of the following is an example of an endothermic reaction?

Accepted Answer

Photosynthesis in plants

Question 18

Which of the following is the correct formula for calculating energy change in a reaction?

Accepted Answer

$$\Delta E = E_{products} - E_{reactants}$$

Question 19

Which of the following best explains why surfactants are important in biological systems?

Accepted Answer

They help form micelles and lipid bilayers, which are essential for cell membrane structure.

Question 20

Which of the following is a correct statement about chemical kinetics?

Accepted Answer

It studies the rate at which chemical reactions occur.

GOB Chemistry Study Notes: Matter, Atoms, Compounds, Organic Molecules, Reactions, and Intermolecular Forces

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