CHEMISTRY

Question 1

What is Chemistry?

Answer 1

The study of matter, its properties, composition, and the changes it undergoes.

Question 2

What are the three states of matter?

Answer 2

Solid, Liquid, Gas.

Question 3

What is the difference between Physical and Chemical Changes?

Answer 3

Physical change alters form without changing composition; chemical change creates new substances.

Question 4

What are Intensive and Extensive Properties?

Answer 4

Intensive: Independent of amount (e.g., density, boiling point); Extensive: Depends on amount (e.g., mass, volume).

Question 5

What is an Atom?

Answer 5

The smallest unit of an element that retains its properties.

Question 6

What are the subatomic particles?

Answer 6

Protons (+), Neutrons (0), Electrons (-).

Question 7

Where are Protons and Neutrons located?

Answer 7

In the nucleus of the atom.

Question 8

What is the Periodic Table?

Answer 8

A chart organizing elements by atomic number and properties.

Question 9

What are Groups and Periods in the Periodic Table?

Answer 9

Groups are vertical columns; Periods are horizontal rows.

Question 10

What is a Mole?

Answer 10

A quantity representing 6.022 x 10^23 particles of a substance (Avogadro’s number).

Question 11

What is Molar Mass?

Answer 11

The mass of one mole of a substance, in grams per mole (g/mol).

Question 12

What is a Chemical Bond?

Answer 12

A force that holds atoms together in compounds.

Question 13

Types of Chemical Bonds

Answer 13

Ionic (transfer of electrons), Covalent (sharing of electrons), Metallic (free-moving electrons in metals).

Question 14

What is a Chemical Reaction?

Answer 14

A process where substances change into new substances with different properties.

Question 15

Types of Chemical Reactions

Answer 15

Synthesis, Decomposition, Single Replacement, Double Replacement, Combustion.

Question 16

What is the Law of Conservation of Mass?

Answer 16

Mass is neither created nor destroyed in a chemical reaction.

Question 17

What is a Solution?

Answer 17

A homogeneous mixture of solute (dissolved substance) and solvent (dissolving medium).

Question 18

What is Solubility?

Answer 18

The ability of a solute to dissolve in a solvent.

Question 19

What is a Saturated Solution?

Answer 19

A solution where the maximum amount of solute is dissolved.

Question 20

What is an Unsaturated Solution?

Answer 20

A solution that can still dissolve more solute.

Question 21

What is a Supersaturated Solution?

Answer 21

A solution that contains more dissolved solute than it normally would at a given temperature.

Question 22

What happens to solubility when temperature increases?

Answer 22

Solubility of solids increases, solubility of gases decreases.

Question 23

What happens to solubility when pressure increases?

Answer 23

Solubility of gases increases (Henry’s Law).

Question 24

What is Miscibility?

Answer 24

The ability of liquids to mix in all proportions (e.g., water and ethanol).

Question 25

What is Immiscibility?

Answer 25

The inability of liquids to mix (e.g., oil and water).

Question 26

What is Boiling Point?

Answer 26

The temperature at which a liquid changes to a gas at a given pressure.

Question 27

What is Ductility?

Answer 27

The ability of a material to be stretched into a wire.

Question 28

What is Cohesion?

Answer 28

The attraction between molecules of the same substance (e.g., water molecules sticking together).

Question 29

What is Adhesion?

Answer 29

The attraction between different substances (e.g., water sticking to glass).

Question 30

What is Surface Tension?

Answer 30

A force that causes the surface of a liquid to contract and resist external force.

Question 31

What is Brittleness?

Answer 31

The tendency of a material to break or shatter when force is applied.

Question 32

What is Agitation?

Answer 32

The stirring or shaking of a solution to increase the rate of dissolution.

Question 33

What is Stirring?

Answer 33

The manual movement of a solution to help dissolve a solute faster.

Question 34

What is Pressure?

Answer 34

The force exerted per unit area by gas particles colliding with surfaces.

Question 35

What is Capillary Action?

Answer 35

The ability of a liquid to flow in narrow spaces without external force, due to cohesion and adhesion.

Question 36

What is Molarity?

Answer 36

A concentration unit defined as moles of solute per liter of solution (mol/L).

Question 37

What is Molecular Formula?

Answer 37

A formula that shows the actual number of atoms of each element in a molecule.

Question 38

What is Empirical Formula?

Answer 38

The simplest whole-number ratio of atoms in a compound.

Question 39

What is Viscosity?

Answer 39

A measure of a liquid's resistance to flow.

Question 40

What happens to viscosity when temperature increases?

Answer 40

Viscosity decreases (liquids flow more easily).

Question 41

What happens to viscosity when temperature decreases?

Answer 41

Viscosity increases (liquids become thicker).

Question 42

What is Temperature?

Answer 42

A measure of the average kinetic energy of particles in a substance.

Question 43

What happens to particle movement when temperature increases?

Answer 43

Particles move faster and spread apart.

Question 44

What happens to particle movement when temperature decreases?

Answer 44

Particles move slower and come closer together.

Question 45

What happens to gas pressure when volume decreases?

Answer 45

Pressure increases (Boyle's Law).

Question 46

What happens to gas pressure when temperature increases?

Answer 46

Pressure increases (Gay-Lussac’s Law).

Question 47

What is an Acid?

Answer 47

A substance that donates H+ ions and has a pH below 7.

Question 48

What is a Base?

Answer 48

A substance that donates OH- ions and has a pH above 7.

Question 49

What is Neutralization?

Answer 49

A reaction between an acid and a base to form water and salt.

Question 50

What is Stoichiometry?

Answer 50

The calculation of reactants and products in a chemical reaction.

Question 51

What is the Ideal Gas Law?

Answer 51

PV = nRT, where P = pressure, V = volume, n = moles, R = gas constant, T = temperature.

Question 52

What is Thermochemistry?

Answer 52

The study of energy changes in chemical reactions.

Question 53

What is an Exothermic Reaction?

Answer 53

A reaction that releases heat energy.

Question 54

What is an Endothermic Reaction?

Answer 54

A reaction that absorbs heat energy.

Question 55

What is an Atom?

Answer 55

The smallest unit of an element that retains its chemical properties.

Question 56

What is a Molecule?

Answer 56

A group of two or more atoms bonded together.

Question 57

What is a Substance?

Answer 57

A form of matter with a uniform and definite composition, either an element or a compound.

Question 58

What are Van der Waals Forces?

Answer 58

Weak intermolecular forces including dipole-dipole interactions and London dispersion forces.

Question 59

What is a Polar Bond?

Answer 59

A covalent bond where electrons are shared unequally, creating a dipole moment.

Question 60

What is a Non-Polar Bond?

Answer 60

A covalent bond where electrons are shared equally between atoms.

Question 61

What is an Ionic Bond?

Answer 61

A bond formed by the transfer of electrons from a metal to a non-metal, creating charged ions.

Question 62

What is a Covalent Bond?

Answer 62

A bond formed by the sharing of electrons between two non-metal atoms.

Question 63

How do Van der Waals forces affect boiling points?

Answer 63

Stronger Van der Waals forces increase boiling points due to higher intermolecular attraction.

Question 64

What is the difference between Polar and Non-Polar Molecules?

Answer 64

Polar molecules have an uneven charge distribution, while non-polar molecules have an even charge distribution.