how many grams of NH3 are in 250 ml of a 20% (w/v) ammonia solution
20% NH3 w/v means 20g NH3/100 mL soln. So how much must be in 250 mL. Would that be
20g x (250/100) = ??
50g?
To find the number of grams of NH3 in the given solution, we need to use the concept of the weight/volume percentage (w/v%).
The w/v% represents the weight of the solute (in this case, NH3) per volume of the solution (in this case, milliliters or ml).
To solve this problem, follow these steps:
Step 1: Convert the given percentage (20%) to a decimal by dividing it by 100.
20% = 20/100 = 0.20
Step 2: Multiply the converted percentage by the volume of the solution in milliliters (250 ml) to find the weight of NH3:
Weight of NH3 = 0.20 * 250 ml
Step 3: Convert the weight of NH3 from milliliters to grams using the density of NH3.
The density of NH3 is approximately 0.77 g/ml.
Weight of NH3 (g) = 0.20 * 250 ml * 0.77 g/ml
Step 4: Evaluate the equation:
Weight of NH3 (g) = 0.20 * 250 ml * 0.77 g/ml
= 38.5 grams
Therefore, there are 38.5 grams of NH3 in 250 ml of a 20% (w/v) ammonia solution.