Masses in reactions

Question 1

What does the law of conversation of mass state?

Answer 1

No atoms are lost or made during reactions so the mass of products equals the mass of reactants

Question 2

What is the relative formula mass of a compound?

Answer 2

The sum of all the relative atomic masses of all the atoms shown in the formula

Question 3

What is the sum of all relative formula masses of reactants in a balanced equation?

Answer 3

Sum of the relative formula mass of reactants = sum of the relative formula masses of the products

Question 4

What is a mole?

Answer 4

A mole of a substance is its relative atomic mass or relative formula mass in grams

Question 5

What is Avogadro’s constant?

Answer 5

The number of atoms, molecules or ions in a mole of a substance

Question 6

What is the number of Avogadro’s constant?

Answer 6

6.02 x 10²³

Question 7

What is the moles equation?

Answer 7

The number of moles = mass (g) / Ar or Mr

Question 8

What do balanced symbol equations show you?

Answer 8

The number of moles of each substance involved in the reaction

Question 9

What is the reactant that gets used up first?

Answer 9

The first to get used up in a reaction is the limitng reactant

Question 10

What is the limiting reactant?

Answer 10

The reactant that is not in excess