Chemistry Moles, Molar Mass, and Formula Calculations, Chapter 9 Chemical Reaction Notes, Covalent Bonding Notes

What is the SI base unit used to measure the amount of a substance?

The mole

How many representative particles are in one mole?

6.02 x 10^23, known as Avogadro's number

What is the mass of 1 mole of carbon-12?

12 grams

What is the conversion factor from moles to particles?

6.02 x 10^23 particles = 1 mole

What is molar mass?

The mass in grams of one mole of any pure substance

How is the molar mass of an element related to its atomic mass?

The molar mass is numerically equivalent to its atomic mass and has units of g/mol

What is the procedure to convert moles of a compound to mass?

Use the molar mass of the compound as the conversion factor

How do you find the molar mass of a compound?

Add the molar mass of each element multiplied by the number of moles of that element in the formula

What is percent composition?

The percent by mass of any element in a compound, calculated by dividing the mass of the element by the mass of the compound and multiplying by 100

What distinguishes an empirical formula from a molecular formula?

The empirical formula is the smallest whole-number mole ratio of the elements, while the molecular formula specifies the actual number of atoms of each element in a molecule

What is a hydrate?

A compound that has a specific number of water molecules bound to its atoms

How is the number of water molecules in a hydrate represented?

Written following a dot in the chemical formula (e.g., Na2CO3 • 10H2O)

What happens to a hydrate when it is heated?

Water molecules are released, leaving an anhydrous compound

What is the first step in determining the formula of a hydrate?

Weigh the hydrate before heating

What is the significance of the law of conservation of mass in relation to molar mass?

The molar mass of a compound reflects that mass is conserved in chemical reactions

How do you convert mass to moles of a compound?

Use the inverse of the molar mass as the conversion factor

What is the molar mass of water (H2O)?

Approximately 18 g/mol

How do you convert moles to particles?

Multiply the number of moles by Avogadro's number

What is the molar mass of sodium hydrogen carbonate (NaHCO3)?

Approximately 84 g/mol

What is the empirical formula of hydrogen peroxide?

HO

What is the molecular formula of hydrogen peroxide?

H2O2

How do you calculate the percent composition of an element in a compound?

Divide the mass of the element by the total mass of the compound and multiply by 100

What is the molar mass of aluminum chloride (AlCl3)?

Approximately 133.33 g/mol

What is the relationship between moles and grams for a substance?

Moles can be converted to grams using the molar mass as a conversion factor

What is a chemical reaction?

The process by which one or more substances are rearranged to form different substances.

What are the signs that a chemical reaction may have occurred?

Change in temperature, change in color, odor, gas bubbles, and formation of a solid (precipitate).

What are reactants in a chemical reaction?

The starting substances in a chemical reaction.

What are products in a chemical reaction?

The substances formed as a result of a chemical reaction.

What is a chemical equation?

A statement that uses chemical formulas to show the identities and relative amounts of the substances involved in a chemical reaction.

What factors affect the rate of a chemical reaction?

Temperature of reactants, particle size, agitation (stirring), and concentration of reactants.

What is a catalyst?

A substance that changes the rate of a chemical reaction without being consumed or changed significantly.

What is an exothermic reaction?

A chemical reaction in which heat is released to the surroundings.

What is an endothermic reaction?

A chemical reaction that requires heat, taking in heat or becoming cold.

What is the law of conservation of matter?

The matter and mass of a system must remain constant over time; quantity cannot be added or removed.

What is a coefficient in a chemical equation?

The number written in front of a reactant or product, describing the lowest whole-number ratio of the amounts of all reactants and products.

What is a balanced chemical equation?

An equation where the number of atoms for each element is the same on both sides of the equation.

What is synthesis in chemical reactions?

A reaction where two or more substances come together to make one compound.

What is decomposition in chemical reactions?

A reaction where one compound breaks down into two or more substances.

What is single displacement in chemical reactions?

A reaction where a single element replaces a second element in a compound.

What is double displacement in chemical reactions?

A reaction involving the exchange of positive ions between two compounds.

What is an acid-base (neutralization) reaction?

A reaction between an acid and a base that forms a salt and water.

What is combustion in chemical reactions?

A reaction of an element or compound with oxygen to produce water and carbon dioxide.

What is an ionic bond?

A metal transferring its valence electrons to a nonmetal.

What happens when the charge is positive?

The element will lose its valence electrons (a metal, a cation).

What happens when the charge is negative?

The element will gain valence electrons (a nonmetal, an anion).

What is the octet rule?

Elements will lose, gain, or share electrons to obtain 8 valence electrons, which is stable.

What is a covalent bond?

Atoms in non-ionic compounds share electrons.

What is a molecule?

A molecule is formed when two or more atoms bond covalently.

What types of elements primarily form covalent bonds?

The majority of covalent bonds form between atoms of nonmetallic elements.

What are diatomic molecules?

Diatomic molecules (H2, N2, F2, O2, I2, Cl2, Br2) exist because the two-atom molecules are more stable than the individual atoms.

What is a single covalent bond?

When only one pair of electrons is shared.

What is a double covalent bond?

When two pairs of electrons are shared.

What is a triple covalent bond?

When three pairs of electrons are shared.

What is bond dissociation energy?

The amount of energy required to break a bond.

How does bond length relate to bond strength?

The shorter the bond length, the greater the energy required to break it.

What is an endothermic reaction?

A reaction where more energy is required to break bonds in reactants than is released when new bonds form in products.

What is an exothermic reaction?

A reaction where more energy is released than is required to break the bonds in the initial reactants.

What is the significance of prefixes in naming binary molecular compounds?

Prefixes indicate the number of atoms of each element present in the compound.

What is a binary acid?

An acid that contains hydrogen and one other element.

What is an oxyacid?

An acid that contains both a hydrogen atom and an oxyanion (oxygen).

What is resonance in molecular structures?

A condition that occurs when more than one valid Lewis structure can be written for a molecule or ion.

What does the VSEPR model determine?

The shape of a molecule, which determines many of its physical and chemical properties.

What is hybridization?

A process in which atomic orbitals mix and form new, identical hybrid orbitals.