If you put 0.25 molar solution of Sodium Chloride (NaCl) in 100 ml of distilled water. ... how much salty precipitate remains in an evaporating dish from 10 ml of solution?
mols NaCl = M x L = 0.25 x 0.01 = ?
g NaCl in the dish is mols x molar mass = ? and that's the amount in the dish after evaporation of the water.
ok, in 100ml you add .25M. The question is how much of the .25M solution did you add to the 100ml?
I think the answer to that is 10 mL.
To determine how much salty precipitate remains in an evaporating dish from 10 ml of the solution, we need to calculate the amount of salt in the solution and then consider the remaining solution after evaporation.
First, let's calculate the amount of salt in the 0.25 molar solution of Sodium Chloride (NaCl) in 100 ml of distilled water.
A molar solution means that there is 1 mole of the solute substance (NaCl) dissolved in 1 liter of the solution. In this case, we have a 0.25 molar solution, which means there are 0.25 moles of NaCl in 1 liter (1000 ml) of the solution.
To find the moles of NaCl in 100 ml (0.1 liters) of solution, we can use the following formula:
moles = molarity × volume (in liters)
moles = 0.25 mol/L × 0.1 L
moles = 0.025 mol
So, there are 0.025 moles of NaCl in the 100 ml solution.
Next, let's consider the remaining solution after evaporation. We are starting with 10 ml of solution, and we know that the initial solution had a concentration of 0.25 molar (0.025 moles).
To find the remaining amount of salt, we need to know the percentage of the solution that evaporates during the process. Let's assume that none of the salt evaporates and only the water evaporates fully.
Since the amount of salt remains constant, the remaining amount of salt in the evaporating dish will be:
remaining salt = initial amount of salt - evaporated amount of water
The initial amount of salt is 0.025 moles.
The evaporated amount of water can be calculated based on the volume change during evaporation. Assuming the remaining solution is concentrated to a smaller volume (e.g., 1 ml), the volume change is 10 ml - 1 ml = 9 ml.
Note that we are assuming the volume reduction doesn't impact the concentration significantly.
To find the evaporated amount of water in moles, we need to convert the volume (9 ml) to liters:
evaporated water (in liters) = 9 ml ÷ 1000
evaporated water (in liters) = 0.009 L
Since the mole ratio between water and sodium chloride is 1:1, we can assume the evaporated water and the decrease in volume represents the moles of water removed during evaporation.
Therefore, the remaining amount of salt in moles will be:
remaining salt = initial amount of salt - evaporated amount of water
remaining salt = 0.025 mol - 0.009 mol
remaining salt = 0.016 mol
So, there will be 0.016 moles of sodium chloride remaining in the evaporating dish after evaporation from 10 ml of the initial solution.