$$1.81 \times 10$$^{24}$$ atoms

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 sample contains 3.0 moles of carbon atoms. How many atoms are present in the sample? ($$Avogadro's\ Number = 6.022 	imes 10$$^{23}$$ atoms/mole)

Accepted Answer

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

Question 4

Which of the following changes is a chemical change?

Accepted Answer

Iron rusting in the presence of oxygen

Question 5

Which of the following is the correct balanced equation for the combustion of methane ($$CH_4$$)?

Accepted Answer

$$CH_4 + 2O_2$$ \rightarrow $$CO_2 + 2H_2O$

Question 6

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 7

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 8

Which of the following molecules is nonpolar?

Accepted Answer

$$CO_2$$

Question 9

Which of the following is a correct conversion for temperature from Celsius to Kelvin?

Accepted Answer

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

Question 10

Which of the following functional groups is present in alcohols?

Accepted Answer

Hydroxyl group ($$-OH)$$

Question 11

Which of the following best describes an exothermic reaction?

Accepted Answer

A reaction that releases heat to the surroundings

Question 12

Which of the following intermolecular forces is the strongest?

Accepted Answer

Hydrogen bonding

Question 13

A compound contains 12.0 g of carbon and 32.0 g of oxygen. What is the empirical formula of the compound? (Atomic masses: C = 12, O = 16)

Accepted Answer

$$CO_2$$

Question 14

Which of the following is a characteristic of a saturated fatty acid?

Accepted Answer

Contains only single bonds between carbon atoms

Question 15

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

Accepted Answer

They reduce surface tension, allowing the formation of micelles and lipid bilayers

Question 16

Which of the following is the correct formula for calculating the number of moles from mass and molar mass?

Accepted Answer

$$n = \frac{mass}{molar\ mass}$$

Question 17

Which of the following best describes a decomposition reaction?

Accepted Answer

A single compound breaks down into two or more simpler substances

Question 18

Which of the following statements about electronegativity is correct?

Accepted Answer

Electronegativity increases across a period from left to right

Question 19

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

Accepted Answer

Melting of ice

Question 20

Which of the following best describes the function of amphipathic compounds in cell membranes?

Accepted Answer

They have both hydrophilic and hydrophobic regions, allowing them to form bilayers

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

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