Quantitive

Question 1

Conservation of mass

Answer 1

The same atoms are present at the beginning and end of a chemical reaction

Question 2

Relative Formula Mass

Answer 2

Sum of the relative atomic masses of the atoms

Question 3

Avogardo’s constant

Answer 3

1 mole = 6.02×10( to power of 23)

Question 4

Mole equation

Answer 4

Mole = mass / formula mass

Question 5

Steps for mole question

Answer 5

1. Balanced equation
2. Known substance ( mass and Mr)
3. Mole of known substance
4. Ratio ( simplify)
5. Unknown substance ( moles)
6. Unknown substance (Mr and moles)
7. Mass of unknown

Question 6

Concentration equation

Answer 6

Concentration (g/dm3) = Mass (g) / volume (dm3)

If in grams, multiply end result with 1000

Question 7

Atom economy equation

Answer 7

Atom economy = (sum of Mr of useful product / sum of Mr of all reactant) multiplied by 100

Question 8

Yield equation

Answer 8

Yield = (What you actually got/ What u thought you’d get ) multiplied by 100

Question 9

Higher yield …

Answer 9

• reaction is more efficient
• more product is formed
• less water is produced
• higher the profit

Question 10

Importance of atom economy

Answer 10

• economic reasons

- sustainability

Question 11

Why yield can be less than 100%?

Answer 11

• reaction may not go to completion ( it is reversible)
• product may be lost when separated from mixture ( e.g stuck to filter paper)
• reactants may react in various ways

Question 12

Gas volume equation

Answer 12

Volume (dm3) = 24 multiplied moles

Question 13

What effects gas volume?

Answer 13

• higher temperature (greater volume)

- higher pressure ( smaller volume)

Question 14

Volume of 1 mole of any gas at room temp and pressure

Answer 14

24 dm3 or 24 litres

Question 15

What is atom economy for?

Answer 15

To show how much of the reactant was turned into useful products

Question 16

What is percentage yield for?

Answer 16

Shows how much product has been made to what should be made