Unit 2

main points

What is a mole?

A mole is a unit that measures the amount of substance, equivalent to 6.022 x 10^23 particles.

What is molar mass?

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol).

Define Avogadro's number.

Avogadro's number is the number of atoms, ions, or molecules in one mole of a substance, approximately 6.022 x 10^23.

What is the ideal gas law?

The ideal gas law describes the relationship between pressure, volume, temperature, and number of moles of a gas: PV=nRT.

What is the difference between an element and a compound?

An element is a pure substance made of one type of atom, while a compound consists of two or more different types of atoms chemically bonded.

What is a physical change?

A physical change is a change in a substance that does not alter its chemical composition.

What is a chemical change?

A chemical change involves a transformation that alters the chemical identity of a substance.

What is a solution?

A solution is a homogeneous mixture of two or more substances in which one substance (the solute) is dissolved in another (the solvent).

Define concentration in chemistry.

Concentration is the amount of solute present in a given volume of solution, usually expressed in molarity (moles per liter).

What is an acid-base reaction?

An acid-base reaction involves the transfer of protons (H+) between an acid and a base.

What is the pH scale?

The pH scale measures the acidity or basicity of a solution, ranging from 0 (strongly acidic) to 14 (strongly basic).

What are stoichiometry calculations?

Stoichiometry calculations involve using chemical equations to determine the relative amounts of reactants and products.

What is a limiting reactant?

A limiting reactant is the substance that is completely consumed in a chemical reaction, limiting the amount of products formed.

Define enthalpy.

Enthalpy is the total heat content of a system, often used to measure energy changes during chemical reactions.

What is a catalyst?

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.

What does it mean for a solution to be saturated?

A saturated solution is one in which no more solute can dissolve at a given temperature and pressure.

What is the difference between endothermic and exothermic reactions?

Endothermic reactions absorb heat from their surroundings, while exothermic reactions release heat.

What is an ionic bond?

An ionic bond is a type of chemical bond formed between oppositely charged ions through electron transfer.

What is a covalent bond?

A covalent bond is a type of chemical bond where atoms share electrons.

Define oxidation and reduction.

Oxidation is the loss of electrons, while reduction is the gain of electrons in a chemical reaction.