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Flashcards in Module 2.1 Deck (48):
1

Relative isotopic mass

The mass of an atom of an isotope compared with one twelfth of the mass of an atom of carbon 12

2

Relative isotopic mass (Ar)

The weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon 12

3

What is a mass spectrometer used for

- identify an unknown compound.
- find the relative abundance of each isotope of an element.
- determine structural information about molecules.

4

How does a mass spectrometer determine the mass of a molecule or isotope?

By measuring the mass to charge ratio of ions by causing substances to become positive ions. The positive ions are then passed through the apparatus and separated according to their mass and charge. A computer analyses the data on the ions present and produces a mass spectrum.

5

Which atoms do not normally from ions and why?

Be, B, C and Si
Because they require to much energy to transfer the outer shell electrons to form ions.

6

Give the names and formulae of 1+, 1- and 2- molecular ions.

1+ : ammonium NH4 +

1- : hydroxide OH -
Nitrate NO3 -

2- : carbonate CO3 2-
Sulfate SO4 2-

7

Mole

the amount of any substance containing as many particles as there are carbon atoms in 12g of the carbon 12 isotope.

8

Avogadro constant (Na)

The number of atoms per mole of the carbon 12 isotope.

(6.02 * 10^23)

9

Molar mass (M)

The mass per mole of a substance (g mol^-1)

10

Which type of compounds are molecular formulae used for?

Simple molecules

11

What was Avogadros hypothesis

Under the same conditions of temperature and pressure, a mole of any gas would fill the same volume of space.

12

Why is avogadros law now important

It means that we can compare the number of molecules in different gases by comparing their volumes.

13

What if the volume per mole of gas molecules at room temperature and pressure?

24.0 dm^3 mol^-1

14

Molar gas volume

The volume per mole of gas. ( 24.0 dm^3 mol^-1)

15

Do all gases have the same mass or volume?

Same volume but different masses

16

Do gases experience any intermolecular forces?

No

17

What is the concentration of a solution?

The amount of solute in mol dissolved per 1dm3 of solution.

18

Standard solution

A solution of known concentration

19

What are standard solutions used for?

They are used in titrations to determine unknown information about another substance.

20

disadvantages of disposing off by products

It's costly poses potential environmental problems wastes valuable resources

21

What does atom economy consider?

the by products of a chemical reaction as well as the desired product

22

What does a percentage yield tell you?

the efficiency with which reactant are covered into products

23

what does the atom economy tell you?

the proportion of desired products compared with all the products formed

24

what happens if u use a process with a higher atom economy

less waste is produced

25

How does the type of reaction effect atom economy?

addition reactions have an atom economy of 100% Whereas substitution and elimination reactions have an atom economy of less than 100%

26

what do elimination, addition and substitution reactions involve?

Elimination reactions involve the removal of a small molecule from another molecule.

Addition reactions involve two or more reactants joining together.

Substitution reactions involve one atom or molecule swapping places with another.

27

Give the formulae of common acids

H2SO4

HCl

HNO3

CH3COOH (ethanoic acid)

28

What happens when an acid is added to water ?

The acid releases H+ ions into solution

29

What type of acids are good at giving away H+ ions and what type are good at accepting them back?

Strong acids are good at giving up H+ ions and bad at accepting them back. Whereas weak acids are not good at giving them away but are good at accepting H+ ions back

30

Give examples of bases

Metal oxides: Mpg/ Cup

Metal hydroxides: NaOH /Mg(OH)2

Ammonia
Amines- CH3NH2

31

Acid

A chemical that is a proton donor and releases H+ (aq) in solution

32

Alkali

A chemical that reacts with an acid and is soluble in water releasing OH- (aq) ions

33

Base

A chemical that can react with acids and is a proton acceptor

34

Why is ammonia able to react with acids?

When dissolved in water ammonia forms a weak alkaline solution

35

Give the formulae of common alkalines

NaOH
KOH
NH3

36

Equation- ammonia reacts with water to form a weak base

NH3 (aq) + H2O = NH4+ (aq) + OH- (aq)

(= - equilibrium sign)

37

Amphoteric substances

Substances that can react as acids and bases. Eg- glycine

38

what happens if one H+ ion is replaced in sulfuric acid

an acid salt is formed

39

How are salts produced?

by neutralizing acids with bases

40

what is the ionic equation for neutralisation?

H+ (aq) + OH- (aq) 》H2O (l)

41

what are the products when an acid is reacted with a base? (carbonate/ metal oxide/ alkali/ metal)

acid + carbonate 》salt + carbon dioxide + water acid + metal oxide 》 salt + water acid + alkali 》 salt + water Acid + metal 》 salt + hydrogen

42

hydrated

A crystalline compound containing water molecules

43

anhydrous

A substance that contains no water molecules

44

water of crystallisation

water molecules that form an essential part of the crystalline structure of a compound

45

what information does the dot formula give?

it gives the ratio between the number of compound molecules and the number of water molecules within the crystalline structure

46

Why do chemists use oxidation numbers

to keep track of how electrons are being used in bonding

47

How do you find out the oxidation number of different compounds of transition elements

their Roman numerals show their oxidation states

48

oxyanions

negative ions that contain an element along with oxygen