I collected questions from my book which I don't understand plz help me I am stuck plzz.!!!!!!!!
Three different solutions containing the same solute at the same temperature are made to be saturated. Beaker 1 has 200.0 mL, beaker 2 has 500.0 mL and beaker 3 has 1.0 L of solution. Which of these has the highest concentration? Explain your answer.
Calculate the mass, in grams, of solute needed to make each solution 250.0 mL of a 0.100 mol/L CaCl2 solution.
How much of a 3.00 mol/L solution, in Litres, can you make from 675 g of glucose (C6H12O6)?
What is the concentration of sodium ions when 35.0 g of sodium phosphate, Na3PO4, is dissolved in 500. mL of solution? Include the dissociation equation for sodium phosphate.
What volume of a 5.00 mol/L stock solution is needed to make 2.00 L of a 0.125 mol/L solution?
Find the new concentration when 225 mL of a 3.00 mol/L solution has 575 mL of water added to it.
What volume of water must be added to 250.0 mL of a 0.650 mol/L calcium chloride solution to produce a 0.430 mol/L solution?
What is the new concentration if 35 mL of 0.15 mol/L iron (II) nitrate is mixed with 72 mL of a 0.60 mol/L of the same substance?
1 answer
All three solution have the same concentration. Saturation means that the solvent has dissolved all of the solute that it can dissolve. Each beaker contains more solvent but it also contains more solute ( as much more as can be dissolved in the extra solvent) but the concentration in mols/L (OR grams/L) stays the same.
Calculate the mass, in grams, of solute needed to make each solution 250.0 mL of a 0.100 mol/L CaCl2 solution.
How many mols CaCl2 do you need? That's mols = M x L = 0.100 x 0.2500 = 0.02500 mols. Then grams CaCl2 = mols CaCl2 x molar mass CaCl2 = ?
How much of a 3.00 mol/L solution, in Litres, can you make from 675 g of glucose (C6H12O6)?
How many mols do you have in 675 g glucose. That's mols = g/molar mass = 675/180 = ? Then M = mols/L. You know M and mols, solve for L.
What is the concentration of sodium ions when 35.0 g of sodium phosphate, Na3PO4, is dissolved in 500. mL of solution? Include the dissociation equation for sodium phosphate.
Na3PO4 ==> 3Na^+ + [PO4]^3-
How many mols Na3PO4 do you have? mols = g/molar mass = 35.0/164 = about 4.7 estimated. (Check that 164--I may not remember it correctly). Then (Na3PO4) = mols/L = about 4.7 mols/0.500 L = ?
Then (Na^+) will be 3 times that since there are 3 Na^+ in 1 molecule of Na3PO4.
That's half of them. From what you have here, see what you can do with the others.