C2.3 How much? Flashcards Preview

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Flashcards in C2.3 How much? Deck (22):
1

What is the relative mass of a proton

1

2

What is the relative mass of a neutron

1

3

What is the relative mass of an electron

n/a - negligible mass

4

What is a mole?

the relative atomic mass of an element in grams

5

What is the atomic number?

the number of protons

6

What is the mass number?

The number of protons and neutrons

7

What are isotopes?

The same element (same proton number) but different number of neutrons

8

How do you work out a relative formula mass (Mr) of a compound?

add up all the masses of the elements in it in the ratio shown by its formula

9

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

(The mass of element / total mass of compound) x 100

10

What is the equation to work out number of moles?

No. of mols = mass/relative formula mass

11

What should you always do to an equation?

BALANCE IT

12

What is percentage yield?

(actual yield/predicted yield) x100

13

What is atom economy and the equation to calculate it?

making as much useful product as possible
% atom economy = (mass of useful products/mass of all products) x100

14

Why is it important to maximise percentage yield and minimise energy?

to conserve earth's limited resources and reduce pollution also money loss

15

What is a reversible reaction and the symbol for it?

The products can react to make the original reactants again

16

What happens after we add just reactants to a reversible reaction?

will never produce 100% products
some will turn back into reactants, when this is all at the same rate you reach dynamic equilibrium

17

How do we identify additives?

paper chromatography

18

Why are additives added to food?

to improve appearance, taste, shelf life

19

What are modern instrumental instrumental methods of analysis?

gas chromatography and mass spectrometry

20

What is gas chromatography?

separates compounds in a mixture, a carrier gas moves vapour through a column and condense at different rates

21

What is mass spectrometry?

can identify substances quickly and accurately can detect small amounts and provide Ar for gas chromatography through (molecular ion) peaks that show amounts of different substances

22

What is good about modern instrumental methods?

fast, accurate, sensitive