Given:
1. Mass of oxalic acid + weighing paper
2.0355g
2. Mass of weighing paper
0.5219 g
3.volume of oxalic acid solution
250 mL
5. Volume of oxalic acid used in titration
trial 1: 15.o mL Trial 2: 15.0 mL
6. Volume of NaOH solution used in titration:
Trial 1: 12.1 mL trial 2: 12.0 mL
Questions:
1. Mass of oxalic acid
2. molecular weight of oxalic acid
3. number of moles of oxalic acid
4. molarity of oxalic acid
5. number of moles of oxalic acid used in each trial
6. number of moles of NaOH at equivalence point
7. Molarity of NaOH _____M ____M
8. Average of 2 closest trials M NaOH=
To answer these questions, you will need to use various formulas and conversions. Let's go step by step:
1. Mass of oxalic acid:
The mass of oxalic acid can be obtained by subtracting the mass of the weighing paper from the mass of oxalic acid + weighing paper.
Mass of oxalic acid = Mass of oxalic acid + weighing paper - Mass of weighing paper
2. Molecular weight of oxalic acid:
To determine the molecular weight of oxalic acid, you will need to know the chemical formula for oxalic acid (C2H2O4) and look up the atomic masses of its constituent elements (carbon, hydrogen, and oxygen) in the periodic table. The molecular weight can be calculated by adding up the atomic masses of each element in the formula.
3. Number of moles of oxalic acid:
To find the number of moles of oxalic acid, you can use the formula:
Number of moles = Mass / Molecular weight
4. Molarity of oxalic acid:
Molarity is defined as the number of moles of solute per liter of solution. In this case, since the volume of the oxalic acid solution is given in milliliters (mL), you will need to convert it to liters before calculating the molarity. The formula for molarity is:
Molarity (M) = Number of moles / Volume (in liters)
5. Number of moles of oxalic acid used in each trial:
The number of moles of oxalic acid used in each trial can be calculated by multiplying the molarity of the oxalic acid solution with the volume used in the titration. The formula is:
Number of moles = Molarity × Volume (in liters)
6. Number of moles of NaOH at equivalence point:
At the equivalence point in a titration, the moles of the analyte and the moles of the titrant are equal, assuming a stoichiometric reaction. Therefore, the number of moles of NaOH at the equivalence point will be the same as the number of moles of oxalic acid used.
7. Molarity of NaOH:
Using the same approach as calculating the molarity of oxalic acid, you can determine the molarity of NaOH by dividing the number of moles of NaOH at the equivalence point by the volume of NaOH used in the titration (in liters).
8. Average of 2 closest trials M NaOH:
To find the average of the two closest trials, you add the volumes of NaOH used in the two trials and divide it by 2. Then, use this average volume of NaOH and apply the formula from step 7 to calculate the average molarity of NaOH.
To find the answers to the questions, you can follow these step-by-step calculations:
1. Mass of oxalic acid:
Mass of oxalic acid = Mass of oxalic acid + weighing paper - Mass of weighing paper
Mass of oxalic acid = 2.0355 g - 0.5219 g
Mass of oxalic acid = 1.5136 g
2. Molecular weight of oxalic acid:
The molecular weight of oxalic acid is the sum of the atomic masses of its constituent elements.
The atomic masses of carbon (C), hydrogen (H), and oxygen (O) are approximately 12.01 g/mol, 1.008 g/mol, and 16.00 g/mol, respectively.
Molecular weight of oxalic acid (C2H2O4) = (2 * atomic mass of C) + (2 * atomic mass of H) + (4 * atomic mass of O)
Molecular weight of oxalic acid = (2 * 12.01 g/mol) + (2 * 1.008 g/mol) + (4 * 16.00 g/mol)
Molecular weight of oxalic acid = 90.04 g/mol
3. Number of moles of oxalic acid:
Number of moles = Mass / Molecular weight
Number of moles of oxalic acid = Mass of oxalic acid / Molecular weight of oxalic acid
Number of moles of oxalic acid = 1.5136 g / 90.04 g/mol
4. Molarity of oxalic acid:
Molarity = Number of moles / Volume (in liters)
Convert volume from mL to L:
Volume of oxalic acid solution = 250 mL / 1000 mL/L
Molarity of oxalic acid = Number of moles of oxalic acid / Volume of oxalic acid solution
Molarity of oxalic acid = (1.5136 g / 90.04 g/mol) / (250 mL / 1000 mL/L)
5. Number of moles of oxalic acid used in each trial:
Convert volume from mL to L:
Volume of oxalic acid used in trial 1 = 15.0 mL / 1000 mL/L
Volume of oxalic acid used in trial 2 = 15.0 mL / 1000 mL/L
Number of moles of oxalic acid used in trial 1 = Molarity of oxalic acid * Volume of oxalic acid used in trial 1
Number of moles of oxalic acid used in trial 2 = Molarity of oxalic acid * Volume of oxalic acid used in trial 2
6. Number of moles of NaOH at equivalence point:
The stoichiometry of the reaction will determine the number of moles of NaOH at the equivalence point. If the balanced equation is known, it can be used to determine the ratio of moles between oxalic acid and NaOH.
7. Molarity of NaOH:
Molarity of NaOH = Number of moles of NaOH / Volume of NaOH solution
Molarity of NaOH for trial 1 = Number of moles of NaOH in trial 1 / Volume of NaOH used in trial 1
Molarity of NaOH for trial 2 = Number of moles of NaOH in trial 2 / Volume of NaOH used in trial 2
8. Average of 2 closest trials M NaOH:
Average = (Molarity of NaOH in trial 1 + Molarity of NaOH in trial 2) / 2
Please note that the missing details for question 6 make it difficult to provide a specific answer. If you have the balanced equation for the reaction between oxalic acid and NaOH, please provide it, and I can assist you further.