What is Solubility of Gases in Liquids?

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Grade Level:

Class 12

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Definition

What is it?

Solubility of gases in liquids tells us how much gas can dissolve in a specific amount of liquid at a certain temperature and pressure. It's like how much sugar (solid) can dissolve in your tea (liquid), but here we are talking about gases like oxygen in water.

Simple Example

Quick Example

Imagine you open a bottle of cold soda (like Thums Up or Limca). You see bubbles forming and rising. These bubbles are carbon dioxide gas escaping from the liquid. This happens because carbon dioxide was dissolved in the water, and when you opened the bottle, the pressure inside dropped, making the gas less soluble and causing it to escape.

Worked Example

Step-by-Step

PROBLEM: If 0.005 grams of oxygen gas dissolves in 100 ml of water at 25 degrees Celsius and 1 atm pressure, calculate the solubility in grams per liter.

STEP 1: Identify the given values. Mass of oxygen = 0.005 g. Volume of water = 100 ml. --- STEP 2: Convert the volume of water from milliliters (ml) to liters (L). We know 1 L = 1000 ml. So, 100 ml = 100 / 1000 L = 0.1 L. --- STEP 3: Use the formula for solubility: Solubility = (Mass of gas dissolved) / (Volume of liquid). --- STEP 4: Substitute the values into the formula. Solubility = 0.005 g / 0.1 L. --- STEP 5: Calculate the result. Solubility = 0.05 g/L. --- ANSWER: The solubility of oxygen gas in water under these conditions is 0.05 grams per liter.

Why It Matters

Understanding gas solubility is crucial for environmental scientists studying climate change, as it impacts how much CO2 dissolves in oceans. It's also vital in medicine for designing oxygen masks or understanding how divers get 'the bends'. Engineers use this knowledge to design efficient industrial processes, from making soft drinks to purifying water.

Common Mistakes

MISTAKE: Thinking that all gases dissolve equally well in all liquids. | CORRECTION: Different gases have different solubilities in different liquids. For example, CO2 dissolves much better in water than nitrogen does.

MISTAKE: Forgetting that temperature affects gas solubility in liquids. | CORRECTION: Generally, as temperature increases, the solubility of gases in liquids decreases. Think about how hot soda goes flat faster.

MISTAKE: Confusing the effect of pressure on gas solubility with solids. | CORRECTION: For gases, increasing pressure increases solubility in liquids (Henry's Law). For solids, pressure has very little effect on their solubility in liquids.

Practice Questions

Try It Yourself

QUESTION: Why does a cold drink lose its fizz faster when it gets warm? | ANSWER: As the temperature of the cold drink increases, the solubility of carbon dioxide gas in the liquid decreases, causing more gas to escape and making the drink lose its fizz faster.

QUESTION: If 0.008 grams of nitrogen gas dissolves in 200 ml of water at 20 degrees Celsius and 1 atm pressure, what is its solubility in g/L? | ANSWER: 0.04 g/L

QUESTION: A diver experiences 'the bends' if too much nitrogen gas dissolves in their blood at high pressure and then comes out of solution too quickly when they ascend. Which factor is primarily responsible for the increased nitrogen solubility at depth? | ANSWER: High pressure

MCQ

Quick Quiz

Which of the following conditions generally increases the solubility of a gas in a liquid?

Increasing the temperature of the liquid

Decreasing the pressure of the gas above the liquid

Increasing the pressure of the gas above the liquid

Using a liquid that is less dense

The Correct Answer Is:

Increasing the pressure of the gas above the liquid forces more gas molecules into the liquid phase, thereby increasing its solubility. Options A and B would decrease solubility.

Real World Connection

In the Real World

Aquatic life, like fish in a pond, depends heavily on the solubility of oxygen in water. If the water temperature rises too much (due to pollution or climate change), the dissolved oxygen decreases, making it difficult for fish to breathe and survive. This is a big concern for fisheries and river ecosystems across India.

Key Vocabulary

Key Terms

SOLUBILITY: The maximum amount of a substance that can dissolve in a given amount of solvent at a specific temperature and pressure. | ATMOSPHERIC PRESSURE: The pressure exerted by the weight of the air in the atmosphere. | HENRY'S LAW: A law stating that the amount of a gas dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid. | PARTIAL PRESSURE: The pressure that a single gas in a mixture of gases would exert if it alone occupied the same volume at the same temperature.

What's Next

What to Learn Next

Great job understanding gas solubility! Next, you should explore 'Henry's Law' in more detail. It's a key principle that mathematically describes how pressure affects gas solubility, building directly on what you've learned here and helping you solve more complex problems.