Chemistry Basics: 110 One-Liner Questions with Answers

Introduction

Chemistry basics​ provide the foundation for understanding matter, its properties, and the changes it undergoes. Master key concepts in this fundamental science today.

One-Liner Questions on Chemistry Basics

General Concepts

1. What is chemistry?
2. Define matter.
3. What are the three states of matter?
4. What is the smallest unit of an element?
5. What is the difference between an atom and a molecule?
6. What are the main branches of chemistry?
7. What is the periodic table?
8. Define atomic number.
9. Define mass number.
10. What are isotopes?

Atoms and Molecules

11. What are subatomic particles?
12. What is the charge of a proton?
13. What is the charge of an electron?
14. What is the mass of a neutron?
15. What are valence electrons?
16. What is the octet rule?
17. Define chemical bond.
18. What is a covalent bond?
19. What is an ionic bond?
20. What is a metallic bond?

Elements, Compounds, and Mixtures

21. What is an element?
22. Define compound.
23. What is a mixture?
24. How do homogeneous and heterogeneous mixtures differ?
25. What is a solution?
26. What is a solvent?
27. What is a solute?
28. Give an example of a colloid.
29. What is the Tyndall effect?
30. Define suspension.

Chemical Reactions

31. What is a chemical reaction?
32. Name the parts of a chemical equation.
33. What is a reactant?
34. What is a product?
35. Define exothermic reaction.
36. Define endothermic reaction.
37. What is the law of conservation of mass?
38. What is a catalyst?
39. What is activation energy?
40. Name the types of chemical reactions.

Acids, Bases, and Salts

41. What are acids?
42. What are bases?
43. What is the pH scale?
44. What is neutralization?
45. What is a salt in chemistry?
46. Give an example of an acid.
47. Give an example of a base.
48. What is an indicator?
49. What is the pH of pure water?
50. What are strong acids?

Physical and Chemical Changes

51. What is a physical change?
52. What is a chemical change?
53. Give an example of a physical change.
54. Give an example of a chemical change.
55. What are reversible changes?
56. What are irreversible changes?
57. Define sublimation.
58. What is evaporation?
59. What is condensation?
60. What is deposition?

Atomic Structure

61. What is Bohr’s model of the atom?
62. What is an electron configuration?
63. Define atomic orbital.
64. What are energy levels?
65. What is the Pauli exclusion principle?
66. What is Hund’s rule?
67. What is the Aufbau principle?
68. What are quantum numbers?
69. What is Heisenberg’s uncertainty principle?
70. What is Rutherford’s model of the atom?

Periodic Table

71. What is the periodic table?
72. Who invented the periodic table?
73. What is a period in the periodic table?
74. What is a group in the periodic table?
75. Define periodicity.
76. What are noble gases?
77. What are alkali metals?
78. What are halogens?
79. What is the atomic mass of an element?
80. What is a transition metal?

Mole Concept

81. What is a mole in chemistry?
82. Define Avogadro’s number.
83. What is molar mass?
84. What is the formula for calculating the number of moles?
85. What is a molecular formula?
86. What is an empirical formula?
87. What is stoichiometry?
88. What is the percentage composition of a compound?
89. Define limiting reagent.
90. What is molarity?

Thermodynamics

91. What is thermodynamics in chemistry?
92. Define enthalpy.
93. What is entropy?
94. What is Gibbs free energy?
95. Define the first law of thermodynamics.
96. What is the second law of thermodynamics?
97. What is a spontaneous reaction?
98. What is heat capacity?
99. What is specific heat?
100. What is Hess’s law?

Electrochemistry

101. What is electrochemistry?
102. Define oxidation.
103. Define reduction.
104. What is an electrolyte?
105. What is a galvanic cell?
106. What is an electrolytic cell?
107. Define redox reaction.
108. What is the standard electrode potential?
109. What is corrosion?
110. What is electroplating?

Chemistry Basics: Answers

1. Chemistry is the study of matter, its properties, and the changes it undergoes.
2. Matter is anything that has mass and occupies space.
3. Solid, liquid, and gas.
4. The atom.
5. Atoms are individual units; molecules are groups of atoms bonded together.
6. Organic, inorganic, physical, analytical, biochemistry, and theoretical chemistry.
7. A tabular arrangement of elements based on atomic number.
8. The number of protons in an atom’s nucleus.
   
9. The mass number of an atom is the sum of the number of protons and neutrons in its nucleus.
10. Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different mass numbers.

Atoms and Molecules

11. Subatomic particles are particles smaller than an atom, such as protons, neutrons, and electrons.
12. A proton has a positive charge (+1).
13. An electron has a negative charge (-1).
14. A neutron has no charge and a mass approximately equal to a proton.
15. Valence electrons are electrons in the outermost shell of an atom.
16. The octet rule states that atoms tend to gain, lose, or share electrons to achieve a full set of eight valence electrons.
17. A chemical bond is a force that holds atoms together in a molecule.
18. A covalent bond is formed when two atoms share electrons.
19. An ionic bond is formed when one atom donates electrons to another.
20. A metallic bond involves the sharing of free electrons among a lattice of metal atoms.

Elements, Compounds, and Mixtures

21. An element is a substance made of only one type of atom.
22. A compound is a substance composed of two or more elements chemically combined.
23. A mixture is a combination of substances that are not chemically bonded.
24. Homogeneous mixtures are uniform in composition, while heterogeneous mixtures are not.
25. A solution is a homogeneous mixture where one substance is dissolved in another.
26. A solvent is the substance in which the solute dissolves.
27. A solute is the substance dissolved in the solvent.
28. An example of a colloid is milk.
29. The Tyndall effect is the scattering of light by particles in a colloid.
30. A suspension is a heterogeneous mixture with large particles that settle over time.

Chemical Reactions

31. A chemical reaction is a process where substances change into new substances.
32. A chemical equation consists of reactants and products.
33. Reactants are the starting substances in a reaction.
34. Products are the new substances formed in a reaction.
35. An exothermic reaction releases energy.
36. An endothermic reaction absorbs energy.
37. The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction.
38. A catalyst is a substance that increases the rate of a reaction without being consumed.
39. Activation energy is the minimum energy required to start a reaction.
40. Types of reactions include combination, decomposition, displacement, and combustion.

Acids, Bases, and Salts

41. Acids are substances that release hydrogen ions (H⁺) in solution.
42. Bases are substances that release hydroxide ions (OH⁻) in solution.
43. The pH scale measures acidity or alkalinity on a scale of 0 to 14.
44. Neutralization is the reaction between an acid and a base to form salt and water.
45. A salt is an ionic compound formed from the reaction of an acid and a base.
46. An example of an acid is hydrochloric acid (HCl).
47. An example of a base is sodium hydroxide (NaOH).
48. Indicators are substances that change color in acidic or basic solutions.
49. The pH of pure water is 7, which is neutral.
50. Strong acids completely dissociate in solution, such as sulfuric acid (H₂SO₄).

Physical and Chemical Changes

51. A physical change alters the form or appearance of a substance but not its composition.
52. A chemical change results in the formation of new substances with different properties.
53. An example of a physical change is melting ice.
54. An example of a chemical change is rusting of iron.
55. Reversible changes are those that can be undone, like freezing water.
56. Irreversible changes cannot be undone, like burning wood.
57. Sublimation is the direct change of a solid to a gas without passing through the liquid phase.
58. Evaporation is the conversion of a liquid into vapor at the surface.
59. Condensation is the process of gas turning into a liquid.
60. Deposition is the change of a gas directly into a solid without becoming a liquid.

Atomic Structure

61. Bohr’s model describes atoms as having electrons orbiting the nucleus in fixed energy levels.
62. Electron configuration shows the arrangement of electrons in an atom’s orbitals.
63. An atomic orbital is a region where there is a high probability of finding an electron.
64. Energy levels are fixed distances from the nucleus where electrons reside.
65. The Pauli exclusion principle states that no two electrons can have the same set of four quantum numbers.
66. Hund’s rule states that electrons fill orbitals singly before pairing up.
67. The Aufbau principle states that electrons occupy the lowest energy orbital available.
68. Quantum numbers describe the properties of atomic orbitals and their electrons.
69. Heisenberg’s uncertainty principle states it is impossible to know both the position and momentum of an electron simultaneously.
70. Rutherford’s model proposed a dense, positively charged nucleus with electrons orbiting around it.

Periodic Table

71. The periodic table is an arrangement of elements based on their atomic number and properties.
72. Dmitri Mendeleev invented the periodic table.
73. A period in the periodic table is a horizontal row of elements.
74. A group in the periodic table is a vertical column of elements.
75. Periodicity refers to the repeating pattern of chemical properties in elements.
76. Noble gases are unreactive gases in Group 18 of the periodic table.
77. Alkali metals are highly reactive metals in Group 1.
78. Halogens are reactive non-metals in Group 17.
79. Atomic mass is the weighted average mass of an element’s isotopes.
80. Transition metals are elements found in Groups 3-12 that exhibit variable oxidation states.

Mole Concept

81. A mole is the SI unit for the amount of substance, containing 6.022×10236.022×1023 entities (Avogadro’s number).
82. Avogadro’s number is 6.022×10236.022×1023, representing particles in one mole.
83. Molar mass is the mass of one mole of a substance.
84. The formula for moles is moles=given massmolar massmoles=molar massgiven mass​.
85. A molecular formula shows the exact number of atoms in a molecule.
86. An empirical formula gives the simplest whole-number ratio of elements in a compound.
87. Stoichiometry deals with the quantitative relationships in chemical reactions.
88. Percentage composition is the percentage by mass of each element in a compound.
89. The limiting reagent is the reactant that determines the amount of product formed in a reaction.
90. Molarity is the concentration of a solution, defined as moles of solute/liters of solutionmoles of solute/liters of solution.

Thermodynamics

91. Thermodynamics is the study of energy changes in chemical processes.
92. Enthalpy is the total heat content of a system.
93. Entropy is a measure of disorder or randomness in a system.
94. Gibbs free energy determines the spontaneity of a reaction.
95. The first law of thermodynamics states that energy cannot be created or destroyed.
96. The second law of thermodynamics states that entropy in a closed system always increases.
97. A spontaneous reaction occurs naturally without external energy.
98. Heat capacity is the amount of heat required to raise the temperature of a substance by 1°C.
99. Specific heat is the amount of heat per unit mass required to raise the temperature by 1°C.
100. Hess’s law states that the total enthalpy change in a reaction is independent of the pathway taken.

Electrochemistry

101. Electrochemistry studies the relationship between electricity and chemical reactions.
102. Oxidation is the loss of electrons.
103. Reduction is the gain of electrons.
104. Electrolytes are substances that conduct electricity in molten or dissolved states.
105. A galvanic cell generates electricity from spontaneous chemical reactions.
106. An electrolytic cell uses electricity to drive non-spontaneous reactions.
107. A redox reaction involves simultaneous oxidation and reduction.
108. The standard electrode potential measures the tendency of a half-cell to gain or lose electrons.
109. Corrosion is the gradual degradation of metals due to chemical reactions with their environment.
110. Electroplating is the process of depositing a thin layer of metal onto a surface using electrolysis.

Key Takeaways

1. Chemistry explains the composition and behavior of matter.
2. Atomic theory forms the foundation of chemistry.
3. Chemical bonds create compounds from elements.
4. The periodic table organizes elements by properties.
5. Chemical reactions follow the conservation of mass.
6. Acids and bases are classified by pH.
7. Physical and chemical changes alter matter differently.
8. Thermodynamics governs energy changes in reactions.
9. Mole concept simplifies quantitative chemistry.
10. Electrochemistry connects electricity with chemical changes.

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