Redox + Calculations Chemistry

What are metals that exist naturally called and give some examples?

Native Metals

Au: Gold

Pt: Platinum

What is the roasting process?

Roasting is where a sulfide ore is heated strongly in excess oxygen (air).

Used to convert the metal sulfide into a metal oxide, which can then be reduced more easily to the metal.

What is the general word formula for the roasting process?

metal sulfide + oxygen → metal oxide + sulfur dioxide (SO2)

How do you then remove the excess oxygen and which substance do you use to do it?

Through a displacement(redox) reaction.

Carbon (will then make carbon monoxide as a product)

In which case does a displacement reaction not work and what technique is then needed?

For metals which are more reactive than carbon.

Electrolysis

What are the properties of aluminium?

Resistant to corrosion

Light and flexible

Easy to alloy with other metals

Because aluminium has the following properties ; what products are made from it.

Resistant to corrosion

Light and flexible

Easy to alloy with other metals

Cars, pots

Foil, cans

Plane fuselage

Which substance is separated from its ore by blast furnace?

Iron from iron ore

What is introduced to the top of the blast furnace at the start of the process?

Iron ore, limestone and an impure version of carbon

What does the carbon then react with to form?

Carbon reacts with oxygen to form carbon monoxide

What type of reaction is the one with oxygen and carbon?

Exothermic

What is the reaction that follows with iron oxide and carbon monoxide.

Fe2​O3​+3CO→2Fe+3CO2​

Iron 3 oxide + carbon monoxide → Iron + carbon dioxide

What is carbon monoxide in the displacement reaction in the blast furnace?

reducing agent

What is the equation for the thermal decomposition of limestone with state symbols?

CaCO3​(s) → CaO(s) + CO2​(g)

calcium carbonate → calcium oxide + carbon dioxide

What does the calcium oxide then react with to form what?

Sandy impurities to form molten slag

What is the first step for the formation of steel with the equation?

The percentage of carbon is reduced by blowing hot oxygen over pig iron.

C(s)+O2​(g)→CO2​(g)

What is the second step for the formation of steel?

Alloy with other metals to create stainless steel.

Why is stainless steel useful?

It makes iron resistant to rusting

What is the third step for the formation of steel with the equation?

Sulfur impurities are removed by reacting the iron with magnesium powder.

This creates molten slag and is tapped off.

Mg(s)+S(s)→MgS(s)

What is the definition of rust?

The corrosion of iron.

What are some materials used for the barrier method in preventing rust?

Paint/oil/grease

Explain how galvanising prevents rust?

You paint a more reactive metal with iron and so the more reactive metal reacts instead of the iron.

Explain how alloying prevents rust?

Alloying can prevent rust by adding metals that make the iron less reactive or create a protective layer.

How does sacrificial anode prevent rust?

Places a more reactive metal onto the surface of the iron.

What are the equations for:

metal + cold water

metal + steam

metal + cold water → metal hydroxide + hydrogen

metal + steam(H2O) → metal oxide + hydrogen

What is the equation for the reaction of a metal with an acid?

metal + acid → salt + hydrogen

What is oxidation and reduction in term of electrons?

Oxidation is the loss of electrons

Reduction is the gain of electrons

What is the equation for the mass equation?

mass = moles x Molar mass

m = n x M

What is the difference between empirical and molecular formula?

Empirical Formula

• Shows the simplest whole-number ratio of atoms in a compound.

Molecular Formula

• Shows the actual number of atoms of each element in one molecule.