chemistry chapter 6

Question 1

what is relative atomic mass

Answer 1

the relative atomic mass (Ar) is the average mass of the isotopes of an element compared to 1/12 of the mass of an atom

Question 2

what relative molecular mass

Answer 2

the relative molecular mass of a molecular substance is the sum of the relative atomic masses of its constituent elements

Question 2

what is relative formula mass

Answer 2

the relative molecular mass of an ionic compound is more accurately known as the relative formula mass

Question 2

what is the mole

Answer 2

the mole is the unit of amount of substance. the symbol for mole is mol

Question 2

what is the number of particles in a mole

Answer 2

the value 6.02 x 10^23 is called the avogadro number. equal numbers of moles of all substances contain the same number of particles.

Question 3

how do we calculate the involvement of the mole and the number of particles

Answer 3

number of moles ( amount of substance ) = number of particles / 6.02 x 10^23

Question 4

what is molar mass

Answer 4

the molar mass of an element is the mass of one mole of atoms of the element

Question 5

what is the molar mass of a molecular substance

Answer 5

the molar mass of a molecular substance is equal to its relative molecular mass in grams

Question 6

what is the molar mass of an ionic compound

Answer 6

the molar mass of an ionic compound is equal to its relative formula mass in grams

Question 7

how do we calculate the number of moles

Answer 7

number of moles = mass of substance in g/ molar mass of substance g/mol

Question 8

what is the avogadros law

Answer 8

avogadro’s law states that equal volumes of gases, under the same conditions of temperature and pressure, contain the same number of particles

Question 9

how do we calculate the number of moles of a gas

Answer 9

number of moles of gas = volume of gas in cm^3 / 24000 cm^3

Question 10

do balloons of the same volume contain the same number of particles

Answer 10

yes they do. according to the avogadro’s law, the balloons contain the same number of gaseous particles since they have the same volume

Question 11

do the balloons of the same mass contain the same number of particles

Answer 11

if the balloons each contained 0.18g of a different gas, they would not contain the same number of gaseous particles.

Question 12

what does the chemical equation tell us

Answer 12

• the ratio of the number of moles of the reactants and the products
• the physical states of the reactant and products

Question 13

define stoichiometry

Answer 13

stoichiometry is the relationship between the number of moles of reactants and the number of moles of products involved in that chemical equation

Question 14

what are limiting reactants

Answer 14

a limiting reactant is the reactant that is completely used up in a reaction. it limits or determines the amount of products formed in the reaction. the reactants that are not used up in a reaction are said to be in excess