At what temperatures can 40mL of water dissolve the follownig quantities of potassium nitrate?
(a) 35.0g (b) 20.0g
can anyone start me off with a formula or a hint?
on the x axis is temperature (degrees celsius) and on the y axis is solubility (g/100g H20).
Is there any mathematical way to figure this out instead of using the solubility curve.
Yes. Generally the question is how much water will it take to dissolve so much KNO3 at a particular T (and you are given the solubility at those Ts); however, this problem isn't that. You will need a table of solubility vs T or a curve.
grams.
20 g KNO3 is what you want to dissolve.
Your curve shows solubility per 100 g H2O. So we convert 20 g KNO3/40 g H2O to xx g KNO3/100 g H2O.
20 g KNO3 x (100 g H2O/40 g H2O) = 50 g KNO3/100 g H2O. And that is how the solubility curve is plotted. So on the x axis find 50 g KNO3, move straight up to the curve, at the intersection with the curve, move horizontally to the left and read T on the Y axis.
Don't you have somewhere the solubility of KNO3 in water at various temperatures?
Would a solubility curve help?
Yes. What is on the x axis and what is on the y axis?
You want to dissolve 20 g in 40 mL water. We will assume the density of water is 1.00 g/mL; therefore, 40 mL = 40 g water.
How much is that per 100?
20 g x (100/40) = 50 g KNO3
Now look on your curve and read the T that dissolves 50 g KNO3.
Same kind of procedure for 35 g KNO3.
gave answer my question
To determine the temperature at which a certain quantity of potassium nitrate can dissolve in 40mL of water, you will need to consult a solubility chart or table specific to potassium nitrate (KNO3) and water. Solubility charts provide information about the solubility of a substance at different temperatures.
First, let's start with a general formula:
Mass of solute / Volume of solvent = Solubility
In this case, the solute is potassium nitrate (KNO3), and the solvent is water. The given volume of water is 40mL. We'll fill in the given masses of potassium nitrate in part (a) and (b) later.
Now, to find the solubility at a specific temperature, you need to look up the solubility of potassium nitrate in water at that temperature on a solubility chart. The solubility is usually given in grams of solute per 100 grams of solvent (water in this case).
Once you find the solubility value for the given temperature, you can use the formula to calculate the amount of potassium nitrate that can dissolve in 40mL of water.
So, the process involves:
1. Finding the solubility of potassium nitrate in water at a specific temperature.
2. Putting the solubility value into the formula and solving for the mass of solute.
3. Comparing the calculated mass of solute to the given masses in part (a) and (b) to determine if it can dissolve.