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What is a Solvent (dissolving medium)?
Grade Level:
Class 7
Space Technology, EVs, Climate Change, Biotechnology, HealthTech, Robotics, Chemistry, Physics
Definition
What is it?
A solvent is a substance that dissolves another substance, called a solute, to form a solution. Think of it as the 'dissolving medium' that helps other things spread out evenly within it.
Simple Example
Quick Example
Imagine you're making a refreshing glass of nimbu pani (lemonade) on a hot day. You add sugar to water. Here, the water is the solvent because it dissolves the sugar, making it disappear and mix completely.
Worked Example
Step-by-Step
Let's say you want to make a cup of chai. You have water, milk, tea leaves, and sugar.
1. First, you boil water. The water is acting as a solvent for the tea leaves, extracting their flavour.
---2. Then, you add milk. The water and milk mix together, with water still being the primary solvent for the tea flavour compounds.
---3. Finally, you add sugar. The hot chai mixture (mostly water and milk) acts as the solvent, dissolving the sugar crystals.
---4. The sugar particles spread evenly throughout the chai, making it sweet. The water (and milk) successfully dissolved the sugar.
---Answer: The water in the chai acts as the main solvent for the tea leaves and sugar.
Why It Matters
Understanding solvents is crucial in many fields! In Biotechnology, solvents are used to extract medicines from plants. In Space Technology, special solvents are needed to clean sensitive equipment. Even in HealthTech, many medicines are delivered to our bodies as solutions where a solvent carries the active ingredient.
Common Mistakes
MISTAKE: Thinking the solute is always a solid. | CORRECTION: Solutes can be solids (like sugar), liquids (like lemon juice in water), or even gases (like carbon dioxide in soda).
MISTAKE: Believing that a solvent disappears when it dissolves something. | CORRECTION: The solvent is still present; it just mixes with the solute to form a uniform solution.
MISTAKE: Confusing a solvent with a mixture. | CORRECTION: A solvent is *part* of a solution, which is a type of mixture. The solvent is the substance that does the dissolving.
Practice Questions
Try It Yourself
QUESTION: In saltwater, which substance is the solvent? | ANSWER: Water
QUESTION: If you put a drop of ink into a glass of water, what is the solvent? | ANSWER: Water
QUESTION: You are making a solution to clean your bicycle. You mix a cleaning powder into a bucket of water. Identify the solvent and the solute. | ANSWER: Solvent: Water, Solute: Cleaning powder
MCQ
Quick Quiz
Which of these is the best example of a solvent?
Sugar dissolving in tea
Salt dissolving in water
Oil mixing with water
Sand mixing with pebbles
The Correct Answer Is:
B
A solvent is a substance that dissolves another. In option B, water dissolves salt, so water is the solvent. Options A and C describe mixing, but not necessarily dissolving in the solvent sense. Option D is just a mixture of solids.
Real World Connection
In the Real World
In our homes, solvents are everywhere! The spirit or 'thinner' used to clean paint brushes is a solvent. Even the cleaning liquid you use for your phone screen or spectacles contains solvents to dissolve dirt and grease. Our blood is also largely water, acting as a solvent to carry nutrients and oxygen throughout our bodies.
Key Vocabulary
Key Terms
SOLUTION: A uniform mixture formed when a solute dissolves in a solvent | SOLUTE: The substance that gets dissolved in a solvent | DISSOLVE: To mix completely with a liquid and become part of the liquid | MIXTURE: A substance containing two or more different substances that are not chemically joined | AQUEOUS SOLUTION: A solution where water is the solvent
What's Next
What to Learn Next
Now that you know what a solvent is, you're ready to learn about 'What is a Solute?'. Understanding both will help you fully grasp how solutions are formed and why they are so important in our daily lives and in science!
