1) In a laboratory experiment, a 10.0-mL sample of NaCl solution is poured into
ID: 528722 • Letter: 1
Question
1) In a laboratory experiment, a 10.0-mL sample of NaCl solution is poured into an evaporating dish with a mass of 24.10 g. The combined mass of the evaporating dish and NaCl solution is 36.14 g . After heating, the evaporating dish and dry NaClhave a combined mass of 25.30 g .
What is the molarity (M) of the NaCl solution?
If water is added to 10.0 mL of the initial NaCl solution to give a final volume of 54.0 mL , what is the molarity of the diluted NaCl solution?
2)Calculate the mass percent, % (m/m), for the solute in each of the following solutions.
6.0 g of CaCl2 in 60.0 g of CaCl2 solution
Explanation / Answer
1) In a laboratory experiment, a 10.0-mL sample of NaCl solution is poured into an evaporating dish with a mass of 24.10 g. The combined mass of the evaporating dish and NaCl solution is 36.14 g . After heating, the evaporating dish and dry NaClhave a combined mass of 25.30 g .
V = 10 mL of Nacl
m = 24.10 g of dish
mass of NaCl + dish = 36.14
mass of NaCl crystal + dish = 25.30
find molarity of NaCl
V = 10 mL
mass of NaCl =36.14 - 25.30 = 10.84 g of NaCl final
mol = mass/MW = 10.84/58 = 0.186896551 mol
M = mol/V = (0.186896551)/(10*10^-3) = 18.6896 M of NaCl
If water is added to 10.0 mL of the initial NaCl solution to give a final volume of 54.0 mL , what is the molarity of the diluted NaCl solution?
Find new concentration
M1*V1=M2*V2
18.6896 * 10 = M2*54
M2 = 18.6896 *10/54
M2 = 3.461037 M
Q2.
2)Calculate the mass percent, % (m/m), for the solute in each of the following solutions. .
6.0 g of CaCl2 in 60.0 g of CaCl2 solution
CaCl2 = 6 / 60 *100 = 10%
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