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Flashcards in A Level Deck (19)
1

When can percentages shield be calculated?

Only when the substance is in excess

2

Why is theoretical yield hard to achieve?

1. Reaction not completed
2. Side reactions may have occurred
3. Purification may cause loss of product

3

How do you calculate percentage yield?

Actual yield/theoretical yield x 100

4

What is the limiting reageant?

the reactant that is used up first and therefore stops the reaction

5

How can you tell which is the limiting reagent?

In the equation it is the substance with the most moles

6

What is atom economy?

The measure of how well atoms have been utilised

7

How do you calculate atom economy?

Sum of Mr of desired product/Mr of all products x 100
Addition reactions are always 100%

8

What else must be taken into account with efficiency?

Cost of reactants
Percentage yields

9

What is atmospheric pressure equal to?

100 kpa

10

What is the ideal gas equation?

PV=nRT

11

How do you calculate moles using volume?

Mol=V/molar gas volume

12

What units should be used in the ideal gas equation?

M3
K
Pa

13

What two assumptions does the ideal gas equation rely on?

1. Intermolecular forces are negligible
2. The molecules have negligible size relative to their container

14

When do ideal gas equation assumptions apply?

Low pressures and high temperatures

15

What is the real gas equation?

(P+n2a/v2)(v-nb)=nRT

16

What is an acid?

A proton donor

17

What is a base?

A proton accepted that is usually insoluble in water

18

What is an alkali?

A soluble base (produces oh-ion)

19

What does amphoteric mean?

Acts as an acid or a base