I still need help with #3 I'm not sure how I got 1.14M. I have tried to do the problem over, but I not coming up with my original answer of 1.14M. Somehow I am missing a step. Please show work for the 1.14M Thanks Question#9 reads exactly as written.
A student makes a solution by dissolving 55.8 grams of potassium hydroxide in 875.0 grams of water. The resulting solution has a density of 1.07 grams per milliliter.
1. What is the volume of this solution? 870mL
2. Calculate the % concentration of this solution. 55.8/930.8 *100=5.99%
3. Calculate the molar concentration of this solution. ??930.8g/74.02=12.57/.870=14.45M I orginally got 1.14M
4. How many grams of potassium hydroxide are there in 150.0ml of this solution? 9.62g
5. A 200.0ml sample of this solution is diluted to 500.0ml with water. What is its molar concentration?
14.45/x= 500ml/200ml= 5.78M
6. What volume of this solution contains 12.75 grams of potassium hydroxide? ??? .0393L
7. What mass of the original solution contains 25.0 grams of potassium hydroxide? 55.8g/930.8g=25/x=417g
8. What volume of 0.750M H2SO4 solution can be neutralized by 100.0 grams of this solution? 1.2L
9. A student needs 0.600L a 0.100M solution of potassium hydroxide. Describe how this can be done using the original solution and a 1000ml graduated cylinder. ??????
moles KOH = 55.8/56.1 = 0.99465
M = moles/L soln = 0.99465/0.870 L = 1.14328 M which rounds to 1.14M
If I'm missing something on #9 I don't see it. But I reiterate that 50 something mL would be difficult to measure accurately with a 1000 mL graduated cylinder.
Thanks I understand now what I did wrong you have been a big help.
To calculate the volume of the 0.100M solution of potassium hydroxide using the original solution and a 1000ml graduated cylinder, you can follow these steps:
1. Calculate the moles of potassium hydroxide (KOH) needed for the desired concentration of 0.100M in 0.600L (600ml) of solution:
Moles = Molarity * Volume
Moles = 0.100M * 0.600L = 0.060 moles
2. Use the molar concentration of the original solution (14.45M) to determine the volume needed to obtain 0.060 moles of KOH:
Volume = Moles / Molarity
Volume = 0.060 moles / 14.45M = 0.00415L (or 4.15ml)
3. Pour the original solution into the 1000ml graduated cylinder until it reaches the 4.15ml mark. Then, carefully add water to reach the 600ml mark. This will result in a 0.100M solution of potassium hydroxide with a volume of 0.600L.
Note: Be sure to handle chemicals safely and accurately measure the volumes to avoid any errors in the final solution.