Homework - Making salts

• Science
• Lower Secondary (Key Stage 3)

Homework - Making salts

How can salts be made through chemical reactions?

1. By mixing two solids together
2. By reacting an acid with an alkali
3. By heating a metal with a gas
4. By boiling water with sugar

What must be added in correct volumes to make pure salt?

1. Salt and sugar
2. Water and oil
3. Acid and alkali
4. Vinegar and baking soda

What is the next step after stirring the acid and alkali mixture?

1. Gently heating in an evaporating dish
2. Filtering the mixture
3. Adding more water
4. Freezing the solution

How should the salt crystals be dried?

1. Under running water
2. In a warm place
3. In a freezer
4. In direct sunlight

What is left behind after the salt and water react completely?

1. Only salt and water
2. Oil and vinegar
3. Acid and alkali
4. Salt, water, and sugar

What is another name for an alkali?

1. Base
2. Water
3. Salt
4. Acid

When making a pure salt from an acid and an insoluble base, what is the next step after adding excess base?

1. Stir the mixture
2. Filter the mixture
3. Evaporate the mixture
4. Heat the mixture

Why is excess base added to the acid when making a pure salt?

1. To increase the reaction speed
2. To ensure no acid is left
3. To neutralize the base
4. To create a different salt

What is the purpose of evaporating the mixture after filtering out the excess base?

1. To separate the salt
2. To neutralize the acid
3. To enhance the salt's flavor
4. To remove the water

Why do we only use the term alkali for soluble substances?

1. Because they are solid
2. Because they are acidic
3. Because alkalis dissolve
4. Because they are colorful

Rock Salt Mining

Rock Salt Mining happens underground with the salt being physically dug out of the ground. Enormous machines work in a network of gigantic caverns and tunnels, drilling, blasting and crushing rock.

Most of the salt dug out of the ground is used for keeping the roads free of ice during the winter (or “gritting the roads” as it’s more commonly known).

How is rock salt mining carried out?

1. Above ground using manual labor
2. In open-pit mines using explosives
3. On the ocean floor with specialized equipment
4. Underground with machines drilling, blasting, and crushing rock.

What is the primary use of the salt obtained from rock salt mining?

1. Producing table salt for households
2. Creating salt licks for livestock
3. Keeping roads free of ice during winter
4. Seasoning food for consumption

What type of machines are used in rock salt mining?

1. Giant conveyor belts transporting the salt
2. Enormous machines working in caverns and tunnels
3. Small hand tools operated by miners
4. Robotic drones flying underground

Why is salt from rock salt mining commonly used in winter?

1. To grit the roads and keep them ice-free
2. To preserve fruits and vegetables
3. To salt meat for preservation
4. To create brine for pickling

Cut and Blast Mining

In “cut and blast mining” a slot is cut at the base of the rock face using a machine called an under cutter, with a jib carrying a series of tungsten-carbide picks. This is the “cut” part of the process.

The face is then drilled with a series of carefully sited holes, using an electro-hydraulic rotary drill. The holes are charged with explosives and detonated, yielding about 1,200 tonnes of broken rock salt. This is the “blast” part of the process.

The rock blasted from the face is then crushed into pieces about the size of a football and then carried on a conveyor belt to the main crusher. This breaks the rock down into smaller pieces, passing through a sieve to ensure that it has reached the correct size for use in road de-icing. The salt is then hoisted to the surface in skips.

What is the first step in the 'cut and blast mining' process?

1. Charging the holes with explosives
2. Crushing the blasted rock into smaller pieces
3. Drilling the face with carefully sited holes
4. Cutting a slot at the base of the rock face with an undercutter

What is the purpose of the electro-hydraulic rotary drill in the process?

1. Crushing the blasted rock into smaller pieces
2. Drilling a series of carefully sited holes in the rock face
3. Carrying the rock on a conveyor belt
4. Hoisting the salt to the surface in skips

How is the rock blasted from the face further processed?

1. Charging the holes with explosives
2. Cutting a slot at the base of the rock face with an undercutter
3. Crushed into pieces about the size of a football
4. Drilling the face with carefully sited holes

What ensures that the rock salt has reached the correct size for road de-icing?

1. Charging the holes with explosives
2. Drilling the face with carefully sited holes
3. Passing through a sieve after being crushed
4. Cutting a slot at the base of the rock face with an undercutter

How is the salt transported to the surface?

1. Drilling the face with carefully sited holes
2. Cutting a slot at the base of the rock face with an undercutter
3. Charging the holes with explosives
4. Hoisted to the surface in skips