Quantitative Chemistry

Question 1

What is the definition of relative atomic mass?

Answer 1

• The average mass of one atom of an element, relative to 1/12^th of the mass one one atom of carbon-12

Question 2

What is the definition of relative formula mass?

Answer 2

• The mass of one formula unit of a compound, realtive to 1/12^th of the mass of one atom of carbon-12

Question 3

What is a mole?

Answer 3

• The amount of substance which contains the Avogardo Constant of a specified particle or formula unit

Question 4

What is the molar mass?

Answer 4

• The mass of one mole of a substance

Question 5

How do you calculate the number of moles of substance?

Answer 5

• amount of substance (mol) = mass(g)/molar mass(g/mol)

Question 6

What is the molecular formula?

Answer 6

• The acutal number of each type of atom in one molecule of a molecular substance

Question 7

How do you calculate percentage yield?

Answer 7

actual yield/theoretical maximum yield x100

Question 8

How do you calculate moles of gas?

Answer 8

• volume of gas (dm³)/24

Question 9

How do you calculate concentration (2 ways)?

Answer 9

• amount (mol)/volume(dm³)
• mass(g)/volume(dm³)

Question 10

What two methods can be used to determine the formula fo a metal oxide?

Answer 10

• Direct reaction of the metal with oxygen/air (more reactive metals)
• Reduciton of the metal oxide, using hydrogen or methane (less reactive metals)