Metals, Fertilisers and Nuclear Chemistry Flashcards
Where are most naturally-occurring metals found?
Inside rocks — called ores
Where are newer metals made?
Inside reactors.
Can Au make compounds and why?
No, because it is too unreactive.
Give examples of naturally occurring metals.
Gold (Au)
Silver (Ag)
Magnesium (Mg)
Give examples of metals that are not naturally occurring.
Copernicium (Cn)
Nihonium (Nh)
Flerovium (Fl)
What is a metallic bond?
A metallic bond is an electrostatic force of attraction between positive nuclei (ions) and delocalised electrons.
What is the structure of a metal?
A metallic lattice
Why are the electrons in a metal, delocalised?
The atoms are so close that the electrons are attracted to many ions, allowing them to move freely through the lattice.
Give some examples of metallic properties.
conductors of heat
conductors of electricity
malleable
high mpt/bpt
Why can metals conduct electricity?
Because of delocalised electrons moving through the lattice
What is the general equation of a metal reacting with oxygen?
metal + oxygen → metal oxide
Give examples of metal reacting with oxygen.
eg 1: 2Mg + O₂ → 2MgO
eg 2: 4Al + 3O₂ → 2Al₂O₃
What is the general equation of a metal reacting with water?
metal + water → metal hydroxide + hydrogen
Give examples of metals reacting with water.
eg 1: 2Na + 2H₂O → 2NaOH + H₂
eg 2: Ca + 2H₂O → Ca²⁺(OH⁻⁻)₂ + H₂
What is the general equation of a metal reacting with acid?
metal + acid → salt + hydrogen
Give examples of a metal reacting with acid.
eg 1: Li + HCl → LiCl + H₂
eg 2: Zn + HNO₃ → Zn(NO₃)₂ + H₂
State the reactivity series (school metals).
K, Na, Li, Ca
Mg, Al, Zn, Fe, Sn
Cu, Ag
Au
What are the three ways to separate metals from their compounds?
- electrolysis: for most reactive metals
- heat + CO/C: for metals in the middle of reactivity series
- heat: metals of low reactivity
Why does a DC supply need to be used for electrolysis?
Allows the products to be identified.
Give the equation for CuCl₂ being separated using electrolysis.
Cu²⁺(Cl⁻⁻)₂ → Cu + Cl₂
How do you know where to add electrons in an ion-electron equation?
To whichever side is more positive.
If electrons are added to the left in an ion-electron equation, what is that called?
Reduction.
If electrons are added to the right in an ion-electron equation, what is that called?
Oxidation.
Give the ion-electron equation for Al.
Al³⁺ + 3e⁻⁻ → Al
Give the ion-electron equation for oxygen (oxidation).
2O²⁻⁻ → O₂ + 4e⁻⁻
Which metals need electrolysis to be separated?
K, Na, Li, Ca, Mg, Al.
Which metals need heat + C(O) to be separated?
Zn, Fe, Sn, Pb, Cu.
Give the equation for the separation of copper(II) oxide.
CuO + C → Cu + CO₂
Give the ionic equation for the separation of mercury oxide.
Hg²⁻⁻O²⁻⁻ → Hg + O₂
Which metals need heat alone to be separated?
Hg and Ag
What is the definition of electricity?
The flow of charged particles.
Which sources are electricity generated from?
coal, oil, gas, nuclear, wind, waves etc.
How do metals lose/gain electrons in cells?
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.
What does an electrochemical cell need, to conduct?
Two different metals and a conducting solution, called an electrolyte.
What is an electrolyte?
A solution of ions that conducts electricity.
How do ions flow in a half-cell?
Through an ion bridge
What is the relationship between voltage and place in the ECS?
The further apart the metals are in the ECS, the **higher ** the voltage.
The closer they are, the lower the voltage.
Combine these equations to make an overall redox equation
Al → Al³⁺ + 3e⁻⁻
Ag⁺ + e⁻⁻ → Ag
Al + 3Ag⁺ → Al³⁺ + 3Ag
Which pair of metals have the highest voltage?
1) K + Pb / Ca + Ag
2) Zn + Sn / Pb + Ag
3) Cu + Ag / Li + Au
1) Ca + Ag
2) Pb + Ag NOTE: look at the number of equations between them in the databook.
3) Li + Au
What piece of apparatus completes the circuit in a half-cell?
Ion bridge
What does an ion bridge allow for?
The flow of ions.
Give the oxidation and reduction equations that make this redox equation:
Mg + Cu²⁺ → Cu + Mg²⁺
Mg → Mg²⁺ + 2e⁻⁻
Cu²⁺ + 2e⁻⁻ → Cu
How do you write an oxidation equation?
atom → ion + electron(s)
NOTE: Oxidation is the gain of electrons on the right side.
How do you write a reduction equation?
ion + electron(s) → atom
NOTE: Reduction is the gain of electrons at the left side.
What are the three key elements required by plants?
N, P, K
What is the equation for the Haber Process?
N₂ + 3H₂ ⇌ 2NH₃
Fe is a catalyst.
Why can’t NH₃ be used as a fertiliser directly and how do we solve it?
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)
Why can’t we use NH₄OH as a fertiliser, and how do we solve it?
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.
Why is NH₄NO3 a good fertiliser and what other useful fertilisers exist?
It is neutral, soluble and contains 2 N atoms.
Other useful fertilisers include K₃PO₄ and KNO₃.
What is the nuclear notation, mass and charge of alpha radiation?
4
He, Mass: 4, charge: 2+
2
How can an atom become stable?
Having an equal number of protons and neutrons.
What is the nuclear notation, mass and charge of beta radiation?
0
e , Mass: 0, charge: 1-
-1
How does an unstable nucleus become stable?
By emitting radiation from its nucleus.
What is the symbol, mass and charge of gamma radiation?
γ, no mass, no charge
What can alpha be stopped by?
Alpha can be stopped by a sheet of paper or a few cm of air
What can beta be stopped by?
Beta can be stopped by a few mm of aluminium
What can gamma be stopped by?
Gamma can be stopped by a few cm of lead or a few m of concrete
What plate of an electric field will beta be attracted by?
The + plate
What plate of an electric field will gamma be attracted by?
It will go straight through, undeviated
What plate of an electric field will alpha be attracted by?
The - plate
Give the nuclear equation when Sodium emits an alpha particle
23 4 19
Na → He + F
11 2. 9
How is an electron emitted from the nucleus, when electrons don’t exist there?
A neutron breaks apart and forms a proton and an electron (a beta particle)
Give the nuclear equation when oxygen emits a beta particle
18 0 18
O → e + F
8 -1 9
What’s the nuclear notation of a proton?
1
p
1
Give the nuclear equation for when C-14 is bombarded by a neutron.
14 1 15
C + n → C
6 0 6
What is the nuclear equation for when Ca-41 was bombarded by a proton and then emitted an alpha particle.
41 1 4 38
Ca + p → He + K
20 1 2 19
What is the definition of half life?
The time taken for half the nuclei to decay.
Does half-life of a substance ever change?
No
Na-24 has a half-life of 8 days.
a) What % would remain after 24 days?
b) What % decayed after 24 days?
a) 100% → 50% → 25% → 12.5%. 3 half-lives.
b) 100 - 12.5 = 87.5%.
