Suppose you dissolve 40g of potassium nitrate in 100 cm3 of water at 100 C. If half the solution os poured out, how many grams of potassium nitrate will the remaining solution contain?
20 g KNO3.
To find out how many grams of potassium nitrate will remain in the solution, we first need to calculate the initial amount of potassium nitrate dissolved and then determine how much will be left after half of the solution is poured out.
Step 1: Calculate the initial amount of potassium nitrate dissolved:
We are given that 40 grams of potassium nitrate is dissolved in 100 cm3 of water. This means the initial concentration of the solution is 40 grams/100 cm3 or 0.4 g/cm3.
Step 2: Determine the volume of the remaining solution after half is poured out:
If we pour out half of the solution, the volume will reduce by half as well. Therefore, the remaining volume after pouring out half will be 100 cm3 / 2 = 50 cm3.
Step 3: Calculate the remaining amount of potassium nitrate in the solution:
To find the remaining amount of potassium nitrate, we need to multiply the remaining volume (50 cm3) by the initial concentration (0.4 g/cm3).
Remaining amount of potassium nitrate = Remaining volume × Initial concentration
= 50 cm3 × 0.4 g/cm3
= 20 grams
Therefore, the remaining solution will contain 20 grams of potassium nitrate.