Module 2 - [ch2,3,4] (foundations in chemistry)

Question 1

Hydrochloric acid

Answer 1

HCl

Question 2

Sulfuric acid

Answer 2

H₂SO₄

Question 3

Nitric acid

Answer 3

HNO₃

Question 4

ethanoic acid

Answer 4

CH₃COOH

Question 5

bases

Answer 5

metal/alkali oxides
metal hydroxides
metal carbonates
ammonia

Question 6

what makes a chemical a base

Answer 6

can neutralise an acid to form a salt
proton acceptor

Question 7

what is an alkali

Answer 7

a base that dissolves in water
group 1 metal hydroxides
in solution they release hydroxide ion (OH~)

Question 8

gain and loss of oxygen
in terms of hydrogen too

Answer 8

gain - oxidation - removal of hydrogen
loss - reduction - gain of hydrogen

Question 9

what is a redox reaction

Answer 9

a reaction in which both oxidation and reduction occurs

Question 10

what are spectator ions

Answer 10

ions that do not change during a reaction

Question 11

define oxidation in terms of electron transfer and oxidation number

Answer 11

loss of electrons
increase in oxidation number

Question 12

define reduction in terms of electron transfer and oxidation number

Answer 12

gain of electrons
decrease in oxidation number

Question 13

oxidising agent

Answer 13

the chemical accepting the electrons
is reduced

Question 14

reducing agent

Answer 14

chemical that is donating the electrons

Question 15

what do oxidation numbers tell you

Answer 15

how electrons are lost or gained in a reaction

Question 16

what has oxidation number 0

Answer 16

pure elements

Question 17

what is the oxidation number of fluorine

Answer 17

-1

Question 18

what is the oxidation number of oxygen

Answer 18

-2

EXCEPT
in peroxides
-1
when reacted with fluorine
+2

Question 19

why is the oxidation number of oxygen bonded to fluorine +2

Answer 19

fluorine is electronegative enough to remove electrons from the oxygen

Question 20

what is the oxidation number of the halogens

Answer 20

-1

can be positive if bonded to oxygen or fluorine

Question 21

what is the oxidation number of hydrogen

Answer 21

+1

EXCEPT in metal hydrides
-1

Question 22

when an acid is added to water which ion is released into solution

Answer 22

H+
(proton)

Question 23

define acid

Answer 23

proton donor

Question 24

what is a strong acid

Answer 24

fully dissociates in aqueous solution
releases all its H+ ions into solution

Question 25

which base is used to treat acid indigestion

Answer 25

magnesium hydroxide MgOH

Question 26

what are amphoteric substances

Answer 26

substances that can act as acids ands bases

Question 27

acid + carbonate ->

Answer 27

salt, Carbon dioxide , water

Question 28

what is a salt

Answer 28

the product of a reaction in which the H~ ions from the acid are replaced by metal or ammonium ions

Question 29

metal oxide + acid ->

Answer 29

salt , water

Question 30

acid + alkali ->

Answer 30

salt , water

Question 31

metal + acid ->

Answer 31

salt , hydrogen

Question 32

ammonia(aq) + acid ->

Answer 32

ammonium salt

Question 33

what are hydrated crystals

Answer 33

crystalline structure containing water

Question 34

what are anhydrous crystals

Answer 34

crystalline structure containing no water

Question 35

how is water of crystallisation represented

Answer 35

dot formula

Question 36

method to perform a titration

Answer 36

use a pipette to measure volume of solution add indicator swirl ( use a white tile to clearly see end-point ) add acid into burette record initial volume slowly add record volume leftover in burette when end point has been reached repeat for concordant results

Question 37

name indicators

Answer 37

methyl orange (orange - red) phenolphthalein pink ( clear - pink )

Question 38

what is the colour of methyl orange as an indicator

Answer 38

acid - red base - yellow end point - orange

Question 39

how do we indicate an element has more than one stable oxidation number

Answer 39

roman numerals

Question 40

what does the avogadro constant represent

Answer 40

number of atoms in 12g of carbon-12

Question 41

how can you calculate the mass of 1 mole of an element

Answer 41

relative atomic mass in grams e.g 1 mole of carbon-12 has mass 12g

Question 42

moles {} give unit too

Answer 42

moles = mass/Mr mol

Question 43

state avogadro's law

Answer 43

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

Question 44

what volume does 1 mole of a gas occupy under room temperature and pressure

Answer 44

24 dm^3 24000 cm^3

Question 45

define molar gas volume

Answer 45

the volume per mole of gas molecules

Question 46

moles{} gas

Answer 46

moles = volume / 24 (dm^3)

Question 47

what are the ideal ways in which a gas behaves

Answer 47

random movement continuous motion no intermolecular forces experienced exert pressure when they collide with each other no kinetic energy lost in collision when temp increase, kinetic energies of gases increases

Question 48

ideal gas equation {}

Answer 48

pV = nRT pressure*volume = moles*ideal gas constant*Temperature pa * m^3 = mol * Jmol^-1 * K

Question 49

1atm = how many pascals

Answer 49

101 kPa

Question 50

converting from degrees to kelvin?

Answer 50

+273

Question 51

what does concentration of a solution mean

Answer 51

amount of solute dissolved in 1dm^3 of solvent

Question 52

moles{} conc

Answer 52

n = CV moles = concentration * volume mol = moldm^-3 * m^3

Question 53

what is a standard solution

Answer 53

a solution of known concentration

Question 54

what are the steps to preparing a standard solution

Answer 54

weigh the solute dissolve solute using distilled water pour solution into a volumetric flask last traces rinsed and poured in filled to graduation line flask inverted to ensure solution is mixed thoroughly

Question 55

concentrated dilute

Answer 55

large amount of solute per dm^3 of solvent small amount of solute per dm^3 of solvent

Question 56

what is a species in a chemical reaction

Answer 56

any particle that takes part in a reaction

Question 57

what does percentage yield mean

Answer 57

the efficiency to which reactants become products

Question 58

why is percentage yield never 100%

Answer 58

reaction may be at equilibrium the reactants may be impure side reactions may occur reactant or product may be left behind when transferring loss of products during separation and purification

Question 59

percentage yield{}

Answer 59

(actual yield / theoretical yield )* 100

Question 60

what is atom economy

Answer 60

the proportion of products which was desired

Question 61

atom economy {}

Answer 61

( mrdesired product / mr total products ) * 100

Question 62

Describe what you would see when magnesium reacts with an excess of sulfuric acid [2]

Answer 62

Mg/solid dissolves bubbles (hydrogen gas produced)

Question 63

what is meant by the term mole [1]

Answer 63

Amount of substance that has the same number of particles as there are atoms in 12 g of 12C

Question 64

common use for NaClO [1]

Answer 64

bleach disinfectant

Question 65

A student prepares a solution of calcium nitrate by reacting dilute nitric acid, HNO3, with the base calcium hydroxide, Ca(OH)2. Why is calcium nitrate an example of a salt? [1]

Answer 65

The H+ ion in an (nitric) acid has been replaced by a metal ion

Question 66

Explain how the hydroxide ion in aqueous calcium hydroxide acts as a base when it neutralises dilute nitric acid. [1]

Answer 66

Accepts a proton OR accepts H+

Question 67

What term is given to the ‘*x H2O’ part of the formula? [1]

Answer 67

water of crystallisation

Question 68

Explain what is meant by the term salt [1]

Answer 68

when the H+ in an acid is replaced by a metal ion

Question 69

Define an acid. [1]

Answer 69

a proton donor

Question 70

Chewing chalk has been used for many years to combat excess stomach acid and indigestion tablets often contain calcium carbonate, CaCO3. Suggest, with the aid of an equation, how these tablets work. [2]

Answer 70

CaCO3 + HCl -> CaCl2 + H20 + CO2 calcium carbonate neutralises the acid

Question 71

Describe and explain the trend, down the group, in the reactivity of the Group 2 elements with water. [5]

Answer 71

reactivity increases down the group atomic radii increases more electron shielding nuclear attraction decreases electron more easily lost

Question 72

Define the term empirical formula. [1]

Answer 72

simplest whole number ratio of atoms

Question 73

Using aqueous silver nitrate, it is sometimes difficult to distinguish between chloride, bromide and iodide ions. How can aqueous ammonia be used to distinguish between these three ions? [3]

Answer 73

AgCl dissolves in conc NH3 (aq) AgBr partially soluble in NH3 (aq) AgI insoluble in NH3 (aq)

Question 74

Explain what is meant by the term molecular formula. [1]

Answer 74

Number AND type of atoms making up a 1 molecule

Question 75

Define the term relative isotopic mass [2]

Answer 75

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

Question 76

State what is meant by the term isotopes [1]

Answer 76

atoms of an element with the same number of protons but different number of neutrons

Question 77

why do isotopes have similar chemical properties [1]

Answer 77

same number of electrons in the outer shell

Question 78

Define the term relative atomic mass. [3]

Answer 78

weighted mean mass of an atom relative to 1/12th the mass of an atom of carbon-12

Question 79

why would you repeat a titration multiple times

Answer 79

for concordant results (within 0.1cm^3 of each other so you can then reject inaccurate titres