I need help working the problems, I don't know how I got the right answers

Calculate each of the following quantities:
(a) Grams of solute in 185.8 mL of 0.267 M calcium acetate
(b) Molarity of 500. mL of solution containing 21.1g of potassium iodine
(c) Moles of solute in 145.6 L of 0.850 M sodium cyanide

You just posted this question one or two posts below WITH answers and I told you all of the answers were ok.

I know I just posted that question, I got answer from someone but they didn't show me how to work the problem, so I wasn't asking if you could show me how.

(a) Grams of solute in 185.8 mL of 0.267 M calcium acetate

Moles solute = M x L. Then moles x molar mass = grams.

(b) Molarity of 500. mL of solution containing 21.1g of potassium iodine
M = moles/L. 21.1/molar mass KI = mols KI and divide by 0.5L.

(c) Moles of solute in 145.6 L of 0.850 M sodium cyanide
moles = M x L

Note: To work any of this type problem just remember the definition of molarity. M = # moles/L solution. That's all you need. Between that and moles = g/molar mass you can work 99% of the solution problems. The molality ones are slightly different but only slightly. molality = # moles/kg solvent. That's three simple equation will get 99.9% of the solution problems you NORMALLY run into. They won't solve the mole fraction problems but most everything else they will.

Thank you so much

This post really help me a lot. TQ!

Sure! I can help you work through these problems and explain how to get the right answers.

(a) To calculate the grams of solute in a solution, you need to know the molarity and volume of the solution. In this case, you have the molarity (0.267 M) and the volume (185.8 mL) of calcium acetate solution.

To calculate the grams of solute, you can use the formula:

grams of solute = molarity × volume × molar mass

First, convert the volume from milliliters to liters by dividing it by 1000:

185.8 mL ÷ 1000 = 0.1858 L

Next, determine the molar mass of calcium acetate (Ca(CH3COO)2). The molar mass is the sum of the atomic masses of each element in the compound. You can find this information on the periodic table.

The molar mass of calcium (Ca) is approximately 40.08 g/mol, and the molar mass of acetate (CH3COO) is approximately 59.05 g/mol.

Now, substitute the values into the formula:

grams of solute = 0.267 M × 0.1858 L × (40.08 g/mol + 2 × 59.05 g/mol)

Simplify the calculation:

grams of solute = 0.267 M × 0.1858 L × 158.18 g/mol

The final answer will be in grams.

(b) To calculate the molarity of a solution, you need to know the mass of the solute and the volume of the solution. In this case, you have the mass of potassium iodine (21.1 g) and the volume of the solution (500 mL).

First, convert the volume from milliliters to liters by dividing it by 1000:

500 mL ÷ 1000 = 0.5 L

Next, determine the molar mass of potassium iodine (KI). The molar mass of potassium (K) is approximately 39.09 g/mol, and the molar mass of iodine (I) is approximately 126.9 g/mol.

Now, use the formula for molarity:

Molarity (M) = moles of solute ÷ volume of solution (in liters)

To calculate the moles of solute, divide the mass of the solute by the molar mass:

moles of solute = 21.1 g ÷ (39.09 g/mol + 126.9 g/mol)

Simplify the calculation:

moles of solute = 21.1 g ÷ 165.99 g/mol

Now, substitute the values into the formula for molarity:

Molarity = (21.1 g ÷ 165.99 g/mol) ÷ 0.5 L

Simplify the calculation:

Molarity = 0.1270 mol ÷ 0.5 L

The final answer will be in moles per liter (mol/L), which is the unit for molarity.

(c) To calculate the moles of solute in a solution, you need to know the molarity and volume of the solution. In this case, you have the molarity (0.850 M) and the volume (145.6 L) of sodium cyanide solution.

To calculate the moles of solute, you can use the formula:

moles of solute = molarity × volume

Substitute the values into the formula:

moles of solute = 0.850 M × 145.6 L

The final answer will be in moles.