C2.6

Question 1

What is relative atomic mass

Answer 1

The relative mass of an element in comparison to carbon-12 or just its protons + neutrons

Question 2

What is relative formula mass

Answer 2

The mass of all the rams of the atoms/ions in a compound

Question 3

How do you work out the empirical formula of a product when reacting two masses of reactants together

Answer 3

Work out moles of each reactant, grams/rams.
Then divide the number of moles of each reactant by the smallest amount of moles
This ratio is the empirical formula.
E.g.
Ca 10g Cl 17.8g
10/40.   17.8/35.5
0.25.      0.5
.25/.25.  .5/.25
1.              2
CaCl2

Question 4

What is the molecular formula

Answer 4

The true formula for a compound, unsimplified empirical formula

Question 5

How do you make magnesium oxide

Answer 5

Place magnesium in a crucible and place crucible on roaring flame of Bunsen. Occasionally lift lid to add more oxygen into crucible. Keep doing this until there is only a white substance and no more ribbon.

Question 6

How do you work out percentage mass of an element in a compound

Answer 6

Number of element * ram of element
————————————- *100
Relative formula mass of compound

Question 7

What is the yield

Answer 7

The amount of useful product obtained from a reaction

Question 8

What is the theoretical yield

Answer 8

The maximum amount of product you could in theory get from a reaction

Question 9

What is percentage yield and formula

Answer 9

(Actual yield/theoretical yield) * 100

Question 10

What are the three main reasons actual yield isn’t the same as theoretical yeild

Answer 10

Reaction may not be complete when collected.
Some of product is lost during preparation of reaction such as spilling a reactant
There may be unwanted reactions taking place that use up some of the reactants

Question 11

What are by products and waste products

Answer 11

By products are extra products formed in a reaction that weren’t necessarily needed. Waste products are the useless by products

Question 12

Why don’t manufactures like waste products

Answer 12

They’re expensive to safely dispose of
They can harm the environment
Waste products given of such as gases may give the surrounding area a bad smell and reduce the house prices

Question 13

How do manufacturers make profit while keeping the environment clean

Answer 13

Try try to only do reactions that have a high percentage yield
They only do reactions with ad few waste products as possible
The do reactions quickly