Introduction
In this experiment, we will learn to determine the mass percentage of water-soaked by raisins through osmosis in raisins.
Aim
To find the mass percentage of water-soaked by raisins through osmosis in raisins.
Requirements
1. A few raisins with stalked intact,
2. Weight box,
3. Blotting paper,
4. Petri dish,
5. Physical balance.
Theory
1. Raisins perform the process of endosmosis or imbibition of water, which means after keeping it in water for some time, it swells up.
2. They are dehydrated grapes.
3. The process in which a solid substance, when kept in water, imbibes it, resulting in the increase of the volume of the substance, is called the imbibition of water or endosmosis.
4. The solid substance that imbibes the water is called imbibants, and the water that gets imbibed is called imbibate.
5. This happens due to the availability of colloidal substances. For example, Protein, cellulose, starch, etc. Every substance has different imbibing capacities.
6. Cellulose has the weakest imbibing capacity than starch. While the protein has the strongest imbibing capacity.
7. Starchy wheat seeds have more imbibing capacity than proteinaceous pea seeds.
Procedure
Step 1: Weigh some raisins with intact stalks.
Step 2: Put these raisins in a petri dish filled with water.
Step 3: Cover the petri dish.
Step 4: Leave the petri dish undisturbed for one night.
Step 5: On another day, take out the raisins and put them on a blotting paper to remove the extra water.
Step 6: Now, weigh these swollen raisins and note down their weight.
Observation and Calculation
1. Dry raisins weight = x g
2. Swollen raisins weight = y g
3. Weight of water that gets imbibed by raisins = (x – y) g
4. Percentage of water gets imbibed by raisins = x/y * 100 = ……..g
Result
The percentage of water gets imbibed by raisins = x/y * 100 = ……..g.
Precautions
1. Use the raisins with intact stalks.
2. Take proper care while measuring,
3. Use blotting paper to clean extra water.
4. Use enough water to soak the raisins.
Viva Questions and Answers
Q.1 What do you understand about osmosis?
ANS. Osmosis is the phenomenon by which water passes through a semi-permeable, from high concentration to low concentration.
Q.2 How many osmoses are there?
ANS. Two. Exosmosis and endosmosis.
Q.3 What was the aim of our experiment?
ANS. To find the mass percentage of water-soaked by raisins through osmosis in raisins.
Q.4 What do you understand about endosmosis?
ANS. The phenomenon in which water moves inward through a semipermeable membrane is known as endosmosis.
Q.5 What do you understand about exosmosis?
ANS. The phenomenon in which water moves outward through a semipermeable membrane is known as endosmosis.
Q.6 What will happen when we put grapes in a concentrated solution?
ANS. Grapes will shrink due to the process of exosmosis.
Q.7 What process do we have described in this experiment for the swelling of raisins?
ANS. Endosmosis.
Q.8 What do you mean by imbibition?
ANS. The process in which a solid substance, when kept in water, imbibes it, resulting in the increase of volume of the substance, is called the imbibition of water or endosmosis.
Q.9 On what factors does imbibition depend?
ANS. 1. Temperature,
2. Pressure,
3. pH,
4. Tonicity.
Q.10 What do you mean by tonicity?
ANS. The process that deals with the external concentration of a substance is known as its tonicity.
Saquib Siddiqui is a Mechanical Engineer and a content creator. He has special interest in science experiments and teaches the same to school and college students. He is also a technical lead at RUDE LABS PVT. LTD.
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