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2.5

Major VersionM

by Madhushree HS

Introduction

We test and measure the solubility of salt in water, at different temperatures.

Video Overview

    • Adult supervision is recommended while heating.

  1. To make the DIY Test Tube Stand.
  2. Measure 1.4 cm from one end of a straw and make a mark with a sketch pen. Cut the straw at the mark made. This straw piece will measure 0.5 g of common salt. Pinch the straw end (from where you measured) and tape it as shown in the picture.
    • Measure 1.4 cm from one end of a straw and make a mark with a sketch pen.

    • Cut the straw at the mark made. This straw piece will measure 0.5 g of common salt.

    • Pinch the straw end (from where you measured) and tape it as shown in the picture.

    • The pinching is done to avoid the powder sticking to the tape.

    • Making the measuring cup is not necessary if you have access to a weighing scale.

  3. Fill the test tube with 10 ml of water using a dropper. Fill the test tube with 10 ml of water using a dropper. Fill the test tube with 10 ml of water using a dropper.
    • Fill the test tube with 10 ml of water using a dropper.

  4. Measure 0.5 g of common salt. You can do this with 1 full unit of the  straw measure/measuring cup. Transfer the salt into the test tube. Stir the solution using a wooden skewer until the salt dissolves completely.
    • Measure 0.5 g of common salt. You can do this with 1 full unit of the straw measure/measuring cup.

    • Transfer the salt into the test tube.

    • Stir the solution using a wooden skewer until the salt dissolves completely.

  5. Add 7 cups of salt to the test tube. 7 cups of common salt is equal to 3.5 g of common salt. Stir the solution using the skewer until the salt dissolves completely and the solution becomes saturated.
    • Add 7 cups of salt to the test tube.

    • 7 cups of common salt is equal to 3.5 g of common salt.

    • Stir the solution using the skewer until the salt dissolves completely and the solution becomes saturated.

  6. Once the solution becomes saturated, add one more cup of salt using the measuring cup. Stir the contents thoroughly but the salt does not dissolve in water. Take the sketch pen and mark the level of salt in the test tube as shown in the picture.
    • Once the solution becomes saturated, add one more cup of salt using the measuring cup.

    • Stir the contents thoroughly but the salt does not dissolve in water.

    • Take the sketch pen and mark the level of salt in the test tube as shown in the picture.

  7. Using a candle, heat the solution over a  flame for 2 - 3 min as shown in the picture. Hold the test tube in an inclined position while heating. After the test tube is removed from the heat, mark the level of salt in the test tube.
    • Using a candle, heat the solution over a flame for 2 - 3 min as shown in the picture.

    • Hold the test tube in an inclined position while heating.

    • After the test tube is removed from the heat, mark the level of salt in the test tube.

    • Note down the change in the level of salt before and after heating.

  8. Once the salt solution starts cooling down, the additional salt that is dissolved after heating, recrystallises.
    • Once the salt solution starts cooling down, the additional salt that is dissolved after heating, recrystallises.

    • Desired result not achieved -

    • Stir well and observe closely if the salt/sugar is getting dissolved.

    • Make a note of the number of cups of salt/sugar added each time. Making detailed and written records is an integral part of the scientific process.

    • Make sure the water is boiling when you measure the solubility of salt/sugar in boiling water.

    • Use sugar instead salt to check the soubility.

    • Use jaggery powder.

Finish Line

Vishal Bhatt

Member since: 04/26/2017

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81 Guides authored

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