Module 5 NTK Definitions

Question 1

What is the rate-determining step ?

Answer 1

The slowest step of a multi-step reaction/mechanism

Question 2

What is the mole fraction, x(A)?

Answer 2

number of moles of A / total number of moles in gas mixture

Question 3

What is the partial pressure of A, p(A)?

Answer 3

mole fraction of A, x(A) * total pressure, P

Question 4

What is a Bronsted-Lowry acid?

Answer 4

A proton (H+) donor

Question 5

What is a Bronsted-Lowry base?

Answer 5

A proton (H+) acceptor

Question 6

What is a strong acid?

Answer 6

It completely dissociates into its ions in solution to donate a proton

Question 7

What is a weak acid?

Answer 7

It partially dissociates into its ions in solution to donate a proton

Question 8

What is a salt?

Answer 8

A compound produce when a H+ ion from an acid is replaced by a metal ion or another positive ion, e.g. NH4+

Question 9

What is a conjugate acid-base pair?

Answer 9

A pair of two species that transform into each other by the gain or loss of a proton, H+

Question 10

What is pH?

Answer 10

-log[H+]

Question 11

What is [H+]?

Answer 11

10 ^-pH

Question 12

What is pKa?

Answer 12

-log[Ka]

Question 13

What is Ka?

Answer 13

10 ^-pKa

Question 14

What is Kw?

Answer 14

[H+][OH-]

Question 15

What is a buffer solution?

Answer 15

A mixture that minimises pH change on addition of small amounts of acid or base

Question 16

What is lattice enthalpy?

Answer 16

Enthalpy change when one mole of an ionic compound is formed from its gaseous ions

Question 17

What is standard enthalpy change of solution?

Answer 17

The enthalpy change that takes place when one mole of compound (solute) is completely dissolved in water (under standard conditions)

Question 18

What is standard enthalpy change of hydration?

Answer 18

The enthalpy change that takes place when one mole of isolated gaseous ions is dissolved in water forming one mole of aqueous ions (under standard conditions)

Question 19

What is the Gibbs equation?

Answer 19

ΔG = ΔH -TΔS

Question 20

When are reactions feasible/spontaneous?

Answer 20

When ΔG is negative

Question 21

What is the standard electrode (redox) potential?

Answer 21

of a half-cell, is the emf (electron motive force) of a half-cell compared with a standard hydrogen half-cell, measured at 298K with solution concentrations of 1 mol dm^3 and a gas pressure of 100kPa (1 atm)

Question 22

How do you tell which species is going under reduction with Eθ

Answer 22

Species undergoing reduction has the more positive Eθ value?

Question 23

What is a transition element?

Answer 23

A d-block element that forms an ion with an incomplete d sub-shell

Question 24

What is a complex ion?

Answer 24

A transition metal ion bonded to one or more ligands by coordinate bonds

Question 25

What is a ligand?

Answer 25

A molecule or ion that can donate a pair of electrons to the transition metal ion to form a coordinate bond

Question 26

What is a coordinate bond?

Answer 26

Shared pair of electrons in which one of the bonded atoms provides both electrons for the shared pair

Question 27

What is the coordination number?

Answer 27

The total number of coordinate bonds formed between a central metal ion and its ligands

Question 28

What is a monodentate ligand?

Answer 28

A molecule/ion that can donate one pair of electrons to the transition metal ion to form one coordinate bond

Question 29

What is a bidentate ligand?

Answer 29

Donates two lone pairs of electrons to the central metal ion to form two coordinate bonds

Question 30

What is a multidentate ligand?

Answer 30

Donates more than one lone pair of electrons to the central metal ion to form more than one coordinate bond

Question 31

What is an optical isomer?

Answer 31

Stereoisomers that are a pair of **non-superimposable** mirror images of each other