Answer:
A. 1.25M
B. 19.98g
Explanation:
A. Data obtained from the question include the following:
Mass of KMnO4 = 31.6 g
Volume = 160 mL
Molarity =..?
We'll begin by calculating the number of mole KMnO4 in the solution. This is can be obtained as follow:
Mass of KMnO4 = 31.6 g
Molar mass of KMnO4 = 39 + 55 + (16x4) = 158g/mol
Number of mole of KMnO4 =..?
Mole = mass /Molar mass
Number of mole of KMnO4 = 31.6/158 = 0.2 mole
Now, we can obtain the molarity of the solution as follow:
Volume = 160 mL = 160/1000 = 0.16L
Mole of KMnO4 = 0.2 mole
Molarity = mole /Volume
Molarity = 0.2/0.16 = 1.25M
B. Data obtained from the question include the following:
Volume = 300mL
Molarity = 0.74 M
Mass of H2C2O4 =..?
First, we shall determine the number of mole H2C2O4. This is illustrated below:
Volume = 300mL = 300/1000 = 0.3L
Molarity = 0.74 M
Mole of H2C2O4 =?
Mole = Molarity x Volume
Mole of H2C2O4 = 0.74 x 0.3
Mole of H2C2O4 = 0.222 mole
Now, we can easily find the mass of H2C2O4 by converting 0.222 mole to grams as shown below:
Number of mole of H2C2O4 = 0.222 mole
Molar mass of H2C2O4 = (2x1) + (12x2) + (16x4) = 2 + 24 + 64 = 90g/mol
Mass of H2C2O4 =..?
Mass = mole x molar mass
Mass of H2C2O4 = 0.222 x 90
Mass of H2C2O4 = 19.98g
