Chem Definitions

Question 1

Molar mass

Answer 1

The mass in grams of one mole of that substance

Question 2

Molar concentration

Answer 2

The number of moles of solute per unit volume of solution.

Question 3

Electronegitivity

Answer 3

A measure of the tendency of an atom to attract a bonding pair of electrons

Question 4

Intermolecular bond

Answer 4

A bond occurring between atoms within molecules

Question 5

Lewis structure

Answer 5

Are diagrams that represent the outer shell of electrons and show the bonding between atoms of a molecule.

Question 6

Octet rule

Answer 6

Elements tend to combine in such a way that each atom has eight electrons in its valence shell, giving it the same electron configuration as a noble gas.

Question 7

Valence electrons

Answer 7

Outer shell electrons

Question 8

Bond energy

Answer 8

Energy absorbed when bond breaks/ energy released when bond forms

Question 9

Bond length

Answer 9

Length of bond between the atoms (measured in pm- pico metres)

Question 10

Polar covalent bond

Answer 10

A chemical bond that forms when two non-metal atoms share electrons unequally due to the difference in their electronegativity.

Question 11

Dative covalent bond

Answer 11

This type of bond is a description of covalent bonding that occurs between two atoms in which both electrons shared in the bond come from the same atom.

Question 12

What does VSEPR stand for

Answer 12

Valence shell electron Pair repulsion

Question 13

Intramolecular bonds exist…

Answer 13

Intramolecular bonds exist between molecules

Question 14

Intermolecular bonds exist…

Answer 14

Intermolecular bonds exist between molecules or between atoms of noble gases.

Question 15

London forces properties

Answer 15

-the weakest intermolecular force
-is a temporary attractive force that results when the non-polar molecules form temporary dipoles.
-electrons are mobile and can be found at one end of a molecule, thus inducing a temporary dipole.
-low boiling point
-Low IMF
-tetrahedral.

Question 16

EN < 1

Answer 16

Weak polar

Question 17

EN > 1 and <_ 2.1

Answer 17

Polar covalent

Question 18

EN > 2.1

Answer 18

Ionic

Question 19

Dipole-dipole forces properties

Answer 19

-Between polar molecules
-permanent intermolecular forces
-Medium boiling point
-medium IMF

Question 20

Hydrogen bonding properties

Answer 20

-polar molocules
-can only bond with N,F,O
-high boiling point
-highest IMF

Question 21

Trigonal planar:

Answer 21

1 Center atom
3 terminal atom

Question 22

Bent or angular:

Answer 22

1 Center atom
2 terminal atoms
2 lone pairs

Question 23

Tetrahedral

Answer 23

1 Center Atom
4 Terminal Atoms

Question 24

Trigonal pyramidal:

Answer 24

1 Center Atom
3 Terminal Atoms
1 lone pair

Question 25

Trigonal bipyramidal:

Answer 25

1 Center Atom 5 Terminal Atoms

Question 26

Octahedral

Answer 26

1 Center Atom 6 Terminal Atoms

Question 27

Naming Ionic compounds:

Answer 27

-Between metals + non-metals -Metal named first then non-metal -non metal gains ide. E.G: KBr - potassium bromide

Question 28

Using ions to determine name

Answer 28

Cation name stays the same Anion name gets ide at the end E.G: Na+ Cl- - sodium cloride

Question 29

Transition metals:

Answer 29

Roman numerals are used to indicate charge of metal E.G: Cu+ Cl- copper(I) chloride Cu2+ Cl- copper(II) chloride

Question 30

Naming covalent compounds

Answer 30

- between Non-metal - Non-metal -First non-metal named stays the same, second named gets ide at the end. -use (mono, di, tri, tetra, penta, hexa, hepta, octo, nona, deca) to indicate charge E.G: CO - carbon monoxide NO2 - nitrogen dioxide SO3 - sulphur tetraoxide

Question 31

Chemical Formular for: aluminium oxide Calcium sulfide Sodium carbonate

Answer 31

Al2O3 CaS Na2SO4

Question 32

Cm3 to Dm3

Answer 32

1000 cm3 = 1 dm3

Question 33

Define Heat of reaction (🔺H)

Answer 33

The net charge of chemical potential energy of the system.

Question 34

Define Exothermic reactions

Answer 34

Reactions that transfer potential energy into thermal energy.

Question 35

Define endothermic reactions.

Answer 35

Reactions that transfer thermal energy into potential energy.

Question 36

Define activation energy

Answer 36

The minimum energy required to start a chemical reaction.

Question 37

Define Activation complex

Answer 37

a temporary transition state between the reactants and the products

Question 38

Define a catalyst

Answer 38

A substance that increases the rate of the reaction but remains unchanged at the end of the reaction.

Question 39

(🔺H ) refers to?

Answer 39

The number of kilojoules per mole of product formed.