Metals, Fertilisers and Nuclear Chemistry

Question 1

Where are most naturally-occurring metals found?

Answer 1

Inside rocks — called ores

Question 2

Where are newer metals made?

Answer 2

Inside reactors.

Question 3

Can Au make compounds and why?

Answer 3

No, because it is too unreactive.

Question 4

Give examples of naturally occurring metals.

Answer 4

Gold (Au)

Silver (Ag)

Magnesium (Mg)

Question 5

Give examples of metals that are not naturally occurring.

Answer 5

Copernicium (Cn)

Nihonium (Nh)

Flerovium (Fl)

Question 6

What is a metallic bond?

Answer 6

A metallic bond is an electrostatic force of attraction between positive nuclei (ions) and delocalised electrons.

Question 7

What is the structure of a metal?

Answer 7

A metallic lattice

Question 8

Why are the electrons in a metal, delocalised?

Answer 8

The atoms are so close that the electrons are attracted to many ions, allowing them to move freely through the lattice.

Question 9

Give some examples of metallic properties.

Answer 9

conductors of heat

conductors of electricity

malleable

high bpt

Question 10

Why can metals conduct electricity?

Answer 10

Because of delocalised electrons moving through the lattice

Question 11

What is the general equation of a metal reacting with oxygen?

Answer 11

metal + oxygen → metal oxide

Question 12

Give examples of metal reacting with oxygen.

Answer 12

eg 1: 2Mg + O₂ → 2MgO

eg 2: 4Al + 3O₂ → 2Al₂O₃

Question 13

What is the general equation of a metal reacting with water?

Answer 13

metal + water → metal hydroxide + hydrogen

Question 14

Give examples of metals reacting with water.

Answer 14

eg 1: 2Na + 2H₂O → 2NaOH + H₂

eg 2: Ca + 2H₂O → Ca²⁺(OH⁻⁻)₂ + H₂

Question 15

What is the general equation of a metal reacting with acid?

Answer 15

metal + acid → salt + hydrogen

Question 16

Give examples of a metal reacting with acid.

Answer 16

eg 1: Li + HCl → LiCl + H₂

eg 2: Zn + HNO₃ → Zn(NO₃)₂ + H₂

Question 17

State the reactivity series (school metals).

Answer 17

K, Na, Li, Ca

Mg, Al, Zn, Fe, Sn

Cu, Ag

Au

Question 18

What are the three ways to separate metals from their compounds?

Answer 18

• electrolysis: for most reactive metals
• heat + CO/C: for metals in the middle of reactivity series
• heat: metals of low reactivity

Question 19

Why does a DC supply need to be used for electrolysis?

Answer 19

Allows the products to be identified.

Question 20

Give the equation for CuCl₂ being separated using electrolysis.

Answer 20

Cu²⁺(Cl⁻⁻)₂ → Cu + Cl₂

Question 21

How do you know where to add electrons in an ion-electron equation?

Answer 21

To whichever side is more positive.

Question 22

If electrons are added to the left in an ion-electron equation, what is that called?

Answer 22

Reduction.

Question 23

If electrons are added to the right in an ion-electron equation, what is that called?

Answer 23

Oxidation.

Question 24

Give the ion-electron equation for Al.

Answer 24

Al³⁺ + 3e⁻⁻ → Al

Question 25

Give the ion-electron equation for oxygen (oxidation).

Answer 25

2O²⁻⁻ → O₂ + 4e⁻⁻

Question 26

Which metals need electrolysis to be separated?

Answer 26

K, Na, Li, Ca, Mg, Al.

Question 27

Which metals need heat + C(O) to be separated?

Answer 27

Zn, Fe, Sn, Pb, Cu.

Question 28

Give the equation for the separation of copper(II) oxide.

Answer 28

CuO + C → Cu + CO₂

Question 29

Give the ionic equation for the separation of mercury oxide.

Answer 29

Hg²⁻⁻O²⁻⁻ → Hg + O₂

Question 30

Which metals need heat alone to be separated?

Answer 30

Hg and Ag

Question 31

What is the definition of electricity?

Answer 31

The **flow** of **charged particles**.

Question 32

Which sources are electricity generated from?

Answer 32

coal, oil, gas, nuclear, wind, waves etc.

Question 33

How do metals lose/gain electrons in cells?

Answer 33

One metal electrode **loses** electrons through the **wires** to the other metal which **gains** the electrons From the **higher metal** in the ECS, the the **lower metal** in the ECS.

Question 34

What does an electrochemical cell need, to conduct?

Answer 34

Two **different metals** and a conducting solution, called an **electrolyte**.

Question 35

What is an electrolyte?

Answer 35

A **solution of ions** that **conducts** electricity.

Question 36

How do ions flow in a half-cell?

Answer 36

Through an **ion bridge**

Question 37

What is the relationship between voltage and place in the ECS?

Answer 37

The **further apart** the metals are in the ECS, the **higher ** the voltage. The **closer** they are, the **lower** the voltage.

Question 38

Combine these equations to make an overall redox equation Al → Al³⁺ + 3e⁻⁻ Ag⁺ + e⁻⁻ → Ag

Answer 38

Al + 3Ag⁺ → Al³⁺ + 3Ag

Question 39

Which pair of metals have the highest voltage? 1) K + Pb / Ca + Ag 2) Zn + Sn / Pb + Ag 3) Cu + Ag / Li + Au

Answer 39

1) Ca + Ag 2) Pb + Ag NOTE: look at the number of equations between them in the databook. 3) Li + Au

Question 40

What piece of apparatus completes the circuit in a half-cell?

Answer 40

Ion bridge

Question 41

What does an ion bridge allow for?

Answer 41

The flow of ions.

Question 42

Give the oxidation and reduction equations that make this redox equation: Mg + Cu²⁺ → Cu + Mg²⁺

Answer 42

Mg → Mg²⁺ + 2e⁻⁻ Cu²⁺ + 2e⁻⁻ → Cu

Question 43

How do you write an oxidation equation?

Answer 43

atom → ion + electron(s) NOTE: Oxidation is the **gain of electrons** on the **right side**.

Question 44

How do you write a reduction equation?

Answer 44

ion + electron(s) → atom NOTE: Reduction is the **gain of electrons** at the **left side**.

Question 45

What are the three key elements required by plants?

Answer 45

N, P, K

Question 46

What is the equation for the Haber Process?

Answer 46

N₂ + 3H₂ ⇌ 2NH₃ Fe is a catalyst.

Question 47

Why can’t NH₃ be used as a fertiliser directly and how do we solve it?

Answer 47

NH₃ is a gas, but it is soluble in water. So to make an aqueous solution from ammonia (NH₃) we will dissolve it in water. NH₃ (g) + H₂O → NH₄OH (ammonium hydroxide)

Question 48

Why can’t we use NH₄OH as a fertiliser, and how do we solve it?

Answer 48

NH₄OH is **corrosive**. To solve this, we use the **Ostwald Process** to make **nitric acid**: NH₃ + H₂O +O₂ → HNO₃ (nitric acid) By combining the NH₄OH with HNO₃, we **neutralise** the substances to make a good fertiliser: NH₄OH + HNO₃ → NH₄NO₃ (**ammonium nitrate**) + H₂O.

Question 49

Why is NH₄NO3 a good fertiliser and what other useful fertilisers exist?

Answer 49

It is **neutral, soluble** and contains **2 N atoms**. Other useful fertilisers include **K₃PO₄** and **KNO₃**.

Question 50

What is the nuclear notation, mass and charge of alpha radiation?

Answer 50

4 He, Mass: 4, charge: 2+ 2

Question 51

How can an atom become stable?

Answer 51

Having an **equal number** of **protons and neutrons**.

Question 52

What is the nuclear notation, mass and charge of beta radiation?

Answer 52

0 e , Mass: 0, charge: 1- -1

Question 53

How does an unstable nucleus become stable?

Answer 53

By **emitting radiation** from its nucleus.

Question 54

What is the symbol, mass and charge of gamma radiation?

Answer 54

γ, no mass, no charge

Question 55

What can alpha be stopped by?

Answer 55

Alpha can be stopped by a sheet of **paper** or a few cm of **air**

Question 56

What can beta be stopped by?

Answer 56

Beta can be stopped by a few **mm** of **aluminium**

Question 57

What can gamma be stopped by?

Answer 57

Gamma can be stopped by a few **cm of lead** or a few **m of concrete**

Question 58

What plate of an electric field will beta be attracted by?

Answer 58

The **+** plate

Question 59

What plate of an electric field will gamma be attracted by?

Answer 59

It will go **straight through, undeviated**

Question 60

What plate of an electric field will alpha be attracted by?

Answer 60

The **-** plate

Question 61

Give the nuclear equation when Sodium emits an alpha particle

Answer 61

23 4 19 Na → He + F 11 2. 9

Question 62

How is an electron emitted from the nucleus, when electrons don’t exist there?

Answer 62

A **neutron** breaks apart and forms a proton and an **electron** (a beta particle)

Question 63

Give the nuclear equation when oxygen emits a beta particle

Answer 63

18 0 18 O → e + F 8 -1 9

Question 64

What’s the nuclear notation of a proton?

Answer 64

1 p 1

Question 65

Give the nuclear equation for when C-14 is bombarded by a neutron.

Answer 65

14 1 15 C + n → C 6 0 6

Question 66

What is the nuclear equation for when Ca-41 was bombarded by a proton and then emitted an alpha particle.

Answer 66

41 1 4 38 Ca + p → He + K 20 1 2 19

Question 67

What is the definition of half life?

Answer 67

The time taken for **half the nuclei** to **decay**.

Question 68

Does half-life of a substance ever change?

Answer 68

No

Question 69

Na-24 has a half-life of 8 days. a) What % would remain after 24 days? b) What % decayed after 24 days?

Answer 69

a) 100% → 50% → 25% → **12.5%**. 3 half-lives. b) 100 - 12.5 = **87.5%**.