Separating rock salt

Summary

The video demonstrates how to separate salt from sand in a rock salt mixture. First, the rock salt is crushed to break down large salt crystals. Next, the mixture is stirred in water, allowing the salt to dissolve while the sand remains insoluble. The solution is then filtered, leaving the sand behind. Finally, the salt solution is evaporated by heating, causing the water to evaporate and leaving behind salt crystals. The experiment successfully separates the salt from the sand using basic laboratory techniques such as filtration and evaporation.

Takeaways

• 🔨 The experiment involves separating salt from sand in a mixture of rock salt.
• 🧂 Rock salt is a mixture of salt and sand, used on roads in winter to melt ice and improve grip.
• 🧹 Step 1: Crush the rock salt with a mortar and pestle to break down large salt crystals, making them easier to dissolve.
• 💧 Step 2: Add the crushed rock salt to water and stir to dissolve the salt while leaving the sand undissolved.
• 🌡️ The sand is insoluble, so it settles at the bottom of the beaker, while the salt dissolves in the water.
• 🧪 Step 3: Filter the mixture using filter paper to separate the sand from the salt solution.
• 🔍 After filtering, the sand remains in the filter paper, and a salt solution is collected in the beaker.
• 🔥 Step 4: Use evaporation to separate the dissolved salt from the water by heating the solution in an evaporating basin.
• ⏳ As the water evaporates, salt crystals begin to form in the evaporating dish.
• 🎯 The experiment successfully separates the sand and salt, leaving sand in the filter paper and salt crystals in the evaporating dish.

Q & A

What is rock salt and what is it used for?

Rock salt is a mixture of salt and sand, used to melt ice on roads in winter and improve traction, making it less likely for cars to crash.

Why is the rock salt mixture crushed with a mortar and pestle?

The rock salt mixture is crushed to break down large salt crystals into smaller ones, which helps them dissolve more easily in the next step.

What happens when the crushed rock salt is added to water?

When the crushed rock salt is added to water, the salt dissolves, but the sand, which is insoluble, settles at the bottom of the beaker.

What is the purpose of stirring the rock salt mixture in water?

Stirring the mixture helps the salt dissolve more completely, leaving the sand undissolved at the bottom of the beaker.

How is the sand separated from the salt solution?

The sand is separated from the salt solution by filtering the mixture through filter paper. The sand stays in the filter paper, while the dissolved salt passes through.

Why is evaporation used in the final step of the experiment?

Evaporation is used to separate the dissolved salt from the water, leaving behind dry salt crystals once the water evaporates.

Why is only a small amount of salt solution used in the evaporating basin?

A small amount, about 10 milliliters, is used so that the water evaporates quickly, speeding up the process.

What is the role of the Bunsen burner in the evaporation step?

The Bunsen burner heats the salt solution in the evaporating basin, causing the water to evaporate and leaving behind the salt crystals.

How do you know when to stop heating the solution in the evaporation process?

Heating is stopped when salt crystals begin to form in the evaporating basin, indicating that the water is almost fully evaporated.

What are the final products after completing the experiment?

The final products are dry salt crystals in the evaporating basin and sand collected in the filter paper, successfully separated from each other.

Outlines

00:00

🧂 Introduction to Rock Salt and Its Use

The presenter introduces rock salt, a mixture of salt and sand, explaining its practical use in winter to melt ice and improve road grip, reducing the risk of accidents. The experiment aims to separate the salt from the sand in a rock salt mixture.

🔨 Crushing Rock Salt with a Mortar and Pestle

The presenter explains the first step of the experiment, which involves placing rock salt in a mortar and crushing it with a pestle. The goal is to reduce the size of the salt crystals, making them smaller so they can dissolve more easily in the next stage.

💧 Dissolving the Salt in Water

The crushed rock salt is added to a beaker of water, and a stirring rod is used to dissolve the salt. The presenter notes that while the salt dissolves, the sand remains insoluble and settles at the bottom of the beaker.

🧪 Filtering the Mixture to Separate Sand

In the next step, the mixture is filtered using a funnel and filter paper. The goal is to separate the insoluble sand from the salt solution, as the sand is too large to pass through the tiny pores in the filter paper, leaving the dissolved salt in the beaker.

🔥 Evaporating the Water to Obtain Salt Crystals

The salt solution is transferred to an evaporating basin, and about 10 milliliters is heated to evaporate the water. The presenter uses a Bunsen burner, explaining that a small volume speeds up evaporation, and salt crystals start to form as the water evaporates.

🎉 Final Separation: Salt and Sand Successfully Isolated

The presenter concludes the experiment, showing the successful separation of salt and sand. The salt has crystallized in the evaporating basin, and the sand is left in the filter paper, completing the process of separating rock salt.

Keywords

💡Rock salt

Rock salt is a natural mixture of salt (sodium chloride) and sand. In the context of the video, it is used on roads during winter to melt ice and improve traction, making roads safer. The experiment demonstrates how to separate the components of rock salt, specifically the salt and sand.

💡Mortar and pestle

A mortar and pestle is a tool used to crush and grind substances into smaller particles. In the video, the narrator uses it to break down the large crystals of rock salt into smaller pieces to make the salt easier to dissolve in water during the separation process.

💡Dissolving

Dissolving refers to the process where a solid substance (solute) becomes incorporated into a liquid (solvent) to form a solution. In the video, the narrator dissolves the salt in water, leaving behind the sand, which is insoluble, as part of the separation process.

💡Insoluble

Insoluble means a substance that does not dissolve in a liquid. In the video, sand is described as insoluble, meaning it does not dissolve in water, allowing it to be easily separated from the dissolved salt.

💡Filtration

Filtration is a method of separating a solid from a liquid by passing the mixture through a filter, which allows the liquid to pass through but traps the solid. In the video, filtration is used to separate the sand from the salt solution, as the sand particles are too large to pass through the filter paper.

💡Filter paper

Filter paper is a porous material used to separate solids from liquids in filtration. In the video, the filter paper traps the sand while allowing the salt solution to pass through, effectively separating the two components of the rock salt mixture.

💡Evaporation

Evaporation is the process of turning a liquid into vapor, leaving behind any dissolved solids. In the experiment, evaporation is used to remove the water from the salt solution, leaving behind dry salt crystals, which is the final step in separating the salt from the mixture.

💡Bunsen burner

A Bunsen burner is a small gas burner used in laboratories for heating. In the video, the narrator uses the Bunsen burner to heat the evaporating basin and accelerate the evaporation of water from the salt solution, allowing the salt to recrystallize.

💡Crystals

Crystals refer to the solid form of a substance with a highly ordered structure. In the video, the salt crystallizes as the water evaporates, leaving behind solid salt crystals, which are the end product of the separation process.

💡Separation

Separation refers to the process of dividing a mixture into its individual components. The main theme of the video is separating rock salt into its two components: salt and sand. The experiment involves multiple steps, including dissolving, filtration, and evaporation, to achieve this separation.

Highlights

Rock salt is a mixture of salt and sand used to melt ice on roads in winter and improve grip.

The experiment aims to separate the salt from the sand in a rock salt mixture.

Step one involves crushing the rock salt using a mortar and pestle to break the salt crystals into smaller pieces.

Crushing the salt crystals helps them dissolve more easily in water during the next step.

In step two, the crushed rock salt mixture is added to a beaker of water and stirred to dissolve the salt.

Salt dissolves in water, while sand is insoluble and remains at the bottom of the beaker.

Step three involves filtering the mixture to separate the insoluble sand from the salt solution.

The filter paper captures the sand particles, allowing the salt solution to pass through.

After filtering, the sand is left behind in the filter, and the salt remains dissolved in the water.

Evaporation is used to recover the salt by heating the salt solution and allowing the water to evaporate.

Only a small volume of salt solution (10 milliliters) is used for faster evaporation.

The solution is heated in an evaporating basin, and as the water evaporates, salt crystals begin to form.

The experiment is complete when the water has evaporated, leaving behind dry salt crystals.

The separation process successfully isolates the sand in the filter and the salt as crystals after evaporation.

This experiment demonstrates the process of separating mixtures through filtration and evaporation techniques.

Transcripts

so what i've got here is something

called rock salt

and rock salt is actually a mixture of

salt

and sand and it's used to put on the

roads in winter

because it melts the ice on the road and

improves the grip makes it less likely

that cars will crash

in this experiment what i'm going to do

is i'm going to separate the salt

from the sand in the mixture of roxol

now my first step is what i'm going to

do is get a

mortar and a pestle i'm going to place

some of the rock salt

into the mortar and i'm going to crush

it and the reason that i'm going to do

this

is so make sure that the crystals of

salt which are quite big at the moment

are going to be really small i'm going

to break down those crystals make them

small crystals

and that will help them dissolve in the

next stage

step two is that i want to take some of

my crushed

rock salt mixture put some of it into a

beaker of water

in fact let's put all of it in and using

a stirring rod

i'm going to stir the mixture and the

reason i'm going to stir it

is so all of the salt dissolves

so i've given that a good stir and all

of the salt has now dissolved

the sand is insoluble so it hasn't

dissolved so i don't if you can see

but at the bottom of that beaker there

is the insoluble

sand now step three

is i'm going to filter that mixture

so we need a beaker and a funnel

and a piece of filter paper folded into

a cone

so i'm now going to pour my dissolved

rock salt mixture

through my filter paper and the aim of

this

is to remove the sand from the solution

because the sand

grains are going to be too big to fit

through the pores the tiny little holes

in the filter paper the salt

because it's dissolved in the solution

will go through those pores so what i'm

going to get in the bottom of my beaker

is a solution of salt

but all the sand should stay in the

filter paper

so the mix just now finished filtering

and you can see we've got the bottom of

the beaker we've got some

some salt solution and in the filter

you can see that all the sand has been

caught so we've now successfully removed

the sand from our solution

and the salt is now dissolved in that

water there

now i don't want that salt to stay

dissolved in the water because i want

dry salt so the next thing i'm going to

do

is some evaporation and as we saw

earlier evaporation is a technique you

use when you want to separate a liquid

from a soluble substance so salt is a

soluble substance dissolved in

the water so hence

evaporation is the suitable technique

here so i'm going to take about 10

milliliters

of my salt solution

and place it into an evaporating basin

and the reason i only want to use about

10 milliliters is because if i used more

than that it would take

quite a long time for the water to

evaporate so i'm just going to use a

small volume just 10 milliliters

so my solution evaporates quick

so because we're doing evaporation i

then need to heat my

evaporating basin containing

the solution

and the purpose of that is to for the

water to evaporate

so i've just turned off the bunsen

burner when the crystals began to form

inside the

dish i'm just going to allow those

crystals to continue forming there

so heating the solution has evaporated

the water

leaving the salt crystals behind

so there's the sand in the filter

and there's the salt crystals still in

the evaporating basin

so i've been successful i've separated

the salt

from the sand from the rock salt