Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y1 A Level Chemistry OCR > Foundations in chemistry > Flashcards

Foundations in chemistry Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

Explain what is meant by the term relative atomic mass of an element. [2 Marks]

A

(Weighted) mean/average mass of an atom

compared with 1/12th mass of carbon-12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the relative mass of an electron?

A

1/1836

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is meant by the term relative isotopic mass?

A

mass of an isotope relative to 1/12th of carbon-12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

A sample of strontium has a relative atomic mass of 87.73.

The sample consists of:

  • 82.9% Sr-88
  • 6.9% Sr-87
  • one other isotope

Determine the other isotope of strontium in the sample. [2 Marks]

A

Sr-86

(100 x 87.73) - (87 x 6.9) - (88 x 82.9)/10.2 = 86.03 ≈ 86

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define Isotope

A

Isotopes are atoms of the same element with different neutrons and different atomic masses.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why do different isotopes of an element react in the same way? [2 Marks]

A

Neutrons have no impact on chemical reactivity

Reactions involve electrons, isotopes have the same electronic configuration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the charge of an ammonium ion?

A

1+

NH4+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the charge of a hydroxide ion?

A

1-

OH-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the charge of a nitrate ion?

A

1-

NO3-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the charge of a carbonate ion?

A

2-

CO3 (2-)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the charge of a sulfate ion?

A

2-

SO4 (2-)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is an empirical formula?

A

The simplest whole number ration of atoms of each element present in a compound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do you calculate empirical formula?

A
  • divide amounts of each element by the atomic mass
  • divide answers by smallest value
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the Avogadro constant represent?

A

The number of atoms present in one mole of an element.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

State Avogadros law

A

Under the same temperature and pressure. one mole of any gas would occupy the same volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How much volume does a gas occupy, at room temperature and pressure?

A

24dm^3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define molar gas volume

A

The volume per mole of gas molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does the concentration of a solution mean?

A

The amount of solute dissolved in 1dm^3 of solvent.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the formula for calculating moles when concentration and volume are given?

A

Moles (mol) = concentration (mol dm^-3) x volume (dm3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a standard solution?

A

A solution of known concentration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does percentage yield mean?

A

The efficiency of which reactants are converted into products.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are reasons for not obtaining 100% yield? [4 marks]

A
  • The reactants may be impure
  • Side reactions could occur
  • Loss of product during separation and purification
  • Reactants or products may be lost while transferring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How is percentage yield calculated?

A

Percentage yield = actual amount of product (mol) / theoretical amount of product (mol) x 100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does atom economy tell us?

A

The proportion of desired products compared to all the products formed in a reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How is atom economy calculated?

A

Atom economy = (Mr of desired product / sum of the Mr of all products) x 100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What type of reaction has 100% atom economy?

A

Addition reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Define acid

A

Proton donor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Define acid

A

Proton donor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Describe the dissociation of a strong acid

A

Full dissociation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Define base

A

Proton acceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are alkalis?

A

Bases that can dissolve in water to form aqueous hydroxide ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are amphoteric substances?

A

Substances that can act as acids and bases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Acid + Carbonate -> ?

A

Salt + carbon dioxide + water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is a salt?

A

A compound which is formed when the H+ of an ion is replaced by a metal ion or a positive ion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Acid + metal oxide -> ?

A

Salt + water

36
Q

Acid + alkali -> ?

A

Salt + water

37
Q

Acid + metal -> ?

A

Salt + hydrogen

38
Q

What is a shell?

A

A group of atomic orbitals with the same principal quantum number.

39
Q

How many electrons can the 1st shell hold?

A

2

40
Q

How many electrons can the 2nd shell hold?

A

8

41
Q

How many electrons can the 3rd shell hold?

A

18

42
Q

How many electrons can the 4th shell hold?

A

32

43
Q

What is an orbital?

A

A region around the nucleus that can hold up to two electrons with opposite spins.

44
Q

How many electrons can an orbital hold?

A

2

45
Q

What are the 4 types of orbitals?

A

s, p, d, and f orbitals

46
Q

What is the shape of an s-orbital?

A

Spherical

47
Q

What is the shape of a p-orbital?

A

Lobed, hourglass or dumb-bell shape.

48
Q

How many orbitals are found in an s subshell?

A

1

49
Q

How many electrons can be held in an s subshell?

A

2

50
Q

How many orbitals does a p subshell have?

A

3

51
Q

How many electrons can be held in a p subshell?

A

6

52
Q

How many orbitals are present in a d subshell?

A

5

53
Q

How many electrons can be held in a D subshell?

A

10

54
Q

How many orbitals are found in an f subshell?

A

7

55
Q

How many electrons can be held in a F subshell?

A

14

56
Q

Why does 4s orbital fill before 3d?

A

4s orbital has a lower energy level than 3d therefore it is filled before.

57
Q

What is the full electron configuration of krypton?

A

1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6

58
Q

What are the 3 main types of chemical bonds?

A
  • Ionic
  • Covalent
  • Metallic
59
Q

Define ionic bonding

A

The electrostatic attraction between positive and negative ions.

60
Q

Define covalent bonding

A

Electrostatic attraction between a shared pair of electrons and the nucleus

61
Q

Define metallic bonding

A

Electrostatic attraction between the positive metal ions and the sea of delocalised electrons.

62
Q

Why do giant ionic lattices conduct electricity when liquid but not when solid?

A

In a solid state the ions are in fixed positions and cannot move. When they are in liquid state the ions are mobile and can freely carry the charge.

63
Q

Do giant ionic lattices have a high or low melting and boiling point?

A

They have a high melting and boiling point because a large amount of energy is needed to overcome the electrostatic bonds.

64
Q

In what type of solvents do ionic lattices dissolve?

A

Polar solvents

65
Q

How many covalent bonds does carbon form?

A

4

66
Q

How many covalent bonds does oxygen form?

A

2

67
Q

What is average bond enthalpy?

A

The measure of average energy needed to break the bond

68
Q

What are the types of covalent structure?

A
  • simple molecular lattice
  • giant covalent lattice
69
Q

Describe the bonding in simple molecular structures.

A

Atoms within the same molecule are held by strong covalent bonds and different molecules are held by weak intermolecular forces.

70
Q

Why do simple molecular structures have low melting and boiling points?

A

Small amounts of energy are enough to overcome the intermolecular forces.

71
Q

Why can’t simple molecular structures conduct electricity?

A

They have no free charged particles.

72
Q

Simple molecular structures dissolve in what type of solvent?

A

Non polar solvents

73
Q

List some properties of giant covalent structures.

A

-High melting and boiling points
-Non conductors of electricity except graphite
-Insoluble in polar and non polar solvents

74
Q

What are some examples of giant covalent structures?

A

-Diamond
-Graphite
-Silicon dioxide (SiO2)

75
Q

How does graphite conduct electricity?

A

Delocalised electrons present between the layers are able to move freely carrying the charge.

76
Q

Why do giant covalent structures have high melting and boiling points?

A

Strong covalent bonds within the molecules require a lot of energy to be broken.

77
Q

Describe the structure of a diamond.

A

3D tetrahedral structure of C atoms, each C atom is bonded to 4 others.

78
Q

What does the shape of a molecule depend on?

A

-The number of electron pairs in the outer shell
-The number of these electrons with are bonded and lone pairs.

79
Q

Define electronegativity

A

The ability of an atom to attract the pair of electrons in a covalent bond.

80
Q

What does it mean when a bond is non-polar?

A

The electrons in the bond are evenly distributed.

81
Q

What is the most electronegative element?

A

Fluorine

82
Q

How is a polar bond formed?

A

Bonding atoms have different electronegativities.

83
Q

What is meant by intermolecular force?

A

Attractive force between neighbouring molecules.

84
Q

What are the two types of intermolecular forces?

A

-Hydrogen bonding
-Van der Waals’ forces

85
Q

What is the strongest type of intermolecular force

A

Hydrogen bonding

86
Q

What is a lone pair?

A

Electrons on the outer shell that are not involved in bonding.

Y1 A Level Chemistry OCR (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions