GCSE Chemistry Revision "Concentration of Solutions"

Summary

In this Free Science video, viewers learn how to calculate the concentration of a solution in grams per decimeter cubed. The lesson explains that concentration is the mass of solute per given volume of solution, with water often serving as the solvent. The video demonstrates calculations using a formula and offers practice problems. Higher-tier students also explore how changes in solute mass and solution volume affect concentration, making this an informative resource for understanding chemical solutions.

Takeaways

• 🔍 The concentration of a solution is defined as the mass of solute in a given volume of solution.
• 📚 Higher tier students will learn an additional definition of concentration later, but Foundation students only need to learn this one.
• 💧 A solute is a chemical that is dissolved in a solvent, commonly water in chemistry.
• 🔢 The unit of concentration is grams per decimeter cubed (g/dm³), which is equivalent to grams per liter.
• 📐 The concentration is calculated using the formula: concentration (g/dm³) = mass (g) / volume (dm³).
• 📈 A triangle diagram is used to help remember the formula for calculating concentration.
• 🧪 Example calculation: 200 g of a chemical dissolved in water to a final volume of 1 dm³ results in a concentration of 200 g/dm³.
• 🧐 Challenging calculation: 150 g of a chemical dissolved in water to a final volume of 0.5 dm³ results in a concentration of 300 g/dm³.
• 🔄 The equation can be rearranged to calculate either the mass of a solute or the volume of a solution given the concentration.
• 📉 If the mass of solute is increased while the volume remains constant, the concentration increases.
• 📈 If the volume of the solution is increased while the mass of solute remains constant, the concentration decreases.

Q & A

What is the definition of concentration in the context of this video?

Concentration refers to the mass of a solute in a given volume of solution, expressed in grams per decimeter cubed (g/dm³).

What is a solute in chemistry?

A solute is a chemical that is dissolved in a solvent, with water being a common solvent in chemistry.

What is the unit of concentration used in this video?

The unit of concentration used is grams per decimeter cubed (g/dm³), which is equivalent to grams per liter.

How is concentration calculated according to the video?

Concentration is calculated by dividing the mass of the solute in grams by the volume of the solution in decimeters cubed.

What is the concentration of a solution if 200 g of a chemical is dissolved in water to a final volume of 1 dm³?

The concentration would be 200 g/dm³ since the mass (200 g) divided by the volume (1 dm³) equals 200 g/dm³.

How would you calculate the concentration if 150 g of a chemical is dissolved in water to a final volume of 0.5 dm³?

The concentration would be 300 g/dm³, calculated by dividing the mass (150 g) by the volume (0.5 dm³).

What is the mass of a chemical needed to achieve a concentration of 600 g/dm³ in a final volume of 0.4 dm³?

The mass needed would be 240 g, calculated by multiplying the concentration (600 g/dm³) by the volume (0.4 dm³).

How do you find the final volume of a solution containing 200 g of a chemical with a concentration of 800 g/dm³?

The final volume would be 0.25 dm³, found by dividing the mass (200 g) by the concentration (800 g/dm³).

How does increasing the mass of the solute affect the concentration if the volume of the solution remains the same?

Increasing the mass of the solute while keeping the volume constant will increase the concentration of the solution.

What happens to the concentration if the volume of the solution is increased while the mass of the solute remains the same?

If the volume of the solution is increased and the mass of the solute remains the same, the concentration of the solution will decrease.

What additional resources are available for practicing concentration calculations as mentioned in the video?

The video mentions a revision workbook with more questions on concentration, which can be accessed by clicking on the provided link.