Question

10% Na₂CO₃ (W/V) means:

a) 10 grams of Na₂CO₃ dissolved in 100 mL of water
b) 10 grams of Na₂CO₃ dissolved in 1 liter of water
c) 10 milligrams of Na₂CO₃ dissolved in 100 mL of water
d) 10 milligrams of Na₂CO₃ dissolved in 1 liter of water

Answer 1

10% Na2CO3 (W/V) means there are 10 grams of Na2CO3 dissolved in 100 mL of water. This is a weight/volume percent concentration, where '% w/v' represents the mass of the solute in grams per 100 mL of solution.

Step-by-step explanation:

Making sense of chemical solution concentrations is a foundational concept in chemistry, especially when it comes to preparing solutions for a lab. In the case of 10% Na2CO3 (W/V), it indicates that there are 10 grams of sodium carbonate (Na2CO3) dissolved in 100 mL of solution (water being the solvent here). The notation (W/V) stands for weight/volume percent, which is a common way to express concentration in a solution.

• 'a) 10 grams of Na2CO3 dissolved in 100 mL of water' is the correct interpretation of 10% Na2CO3 (W/V).

To further understand solution concentrations, it's important to know the distinction between molarity (M) and molality (m), where molarity is a measure of moles of solute per liter of solution and molality is moles of solute per kilogram of solvent.