The amount of sulphuric acid required by a student to perform an experiment was 1500 ml of 2.30M. Explain how you would prepare the required amount of acid to perform an experiment if the label on the available concentrated commercial sulphuric acid bottle indicates 96.4% by mass acid with specific gravity as 1.84?
Didn’t pay attention. This is acid, so you add water, acid then water to the mark. Shake well. ===> safer that way.
To calculate the amount of concentrated sulphuric acid needed, we can follow these steps:
Step 1: Determine the desired final volume and concentration
The requirement stated that you need 1500 ml of a 2.30M sulphuric acid solution.
Step 2: Understand the properties of the available concentrated sulphuric acid
The label on the concentrated sulphuric acid bottle provides two essential pieces of information: the mass percentage and specific gravity.
- Mass percentage: It indicates that the acid is 96.4% by mass. This means that in every 100 grams of the concentrated sulphuric acid, 96.4 grams are pure acid, and the remaining 3.6 grams are water or impurities.
- Specific gravity: It is given as 1.84. Specific gravity is a measure of the density of a substance compared to the density of water. In this case, it tells us that the concentrated sulphuric acid is 1.84 times denser than water.
Step 3: Calculate the amount of pure acid required
To find the amount of pure acid required, we need to consider the concentration and volume relationship. Concentration is given in moles per liter (M), while the desired volume is given in milliliters (ml).
We can use the equation:
(moles of solute) = (concentration in M) x (volume in liters)
Since we know the desired concentration (2.30M) and volume (1500 ml), we can substitute these values into the equation to find the number of moles of sulphuric acid needed.
1500 ml = 1500/1000 = 1.5 L (converted to liters)
(n moles) = (2.30 M) x (1.5 L)
Step 4: Convert moles of sulphuric acid to grams
To convert moles of sulphuric acid to grams, we need to know the molar mass of sulphuric acid. The molar mass of H2SO4 (sulphuric acid) is:
(1 * 2.02 g/mol (atomic mass of H)) + (1 * 32.07 g/mol (atomic mass of S)) + (4 * 16.00 g/mol (atomic mass of O)) = 98.09 g/mol
Now, we can calculate the mass of pure sulphuric acid required:
(mass in grams) = (n moles) x (molar mass of H2SO4)
Step 5: Adjust for the mass percentage of acid
Since the concentrated sulphuric acid is not 100% pure acid, we need to determine the amount of concentrated sulphuric acid that would contain the calculated mass of pure acid. We can use the mass percentage given (96.4% by mass) to find the required mass of concentrated sulphuric acid.
(mass of concentrated sulphuric acid) = (mass of pure acid) / (mass percentage)
Step 6: Adjust for the specific gravity
The specific gravity tells us how much denser the concentrated sulphuric acid is compared to water. Since we are working with volumes, we need to adjust our calculations to account for the difference in density.
(volume of concentrated sulphuric acid) = (mass of concentrated sulphuric acid) / (density of concentrated sulphuric acid)
Remember that specific gravity is a ratio between the density of the substance and water. Since the specific gravity is given as 1.84, the density of concentrated sulphuric acid is 1.84 times greater than the density of water.
Step 7: Prepare the required amount of acid
Now that we have calculated the volume of concentrated sulphuric acid needed, we can carefully measure and transfer that amount from the commercial bottle into a container.
It's crucial to handle concentrated sulphuric acid with caution as it is highly corrosive and dangerous. Ensure you use appropriate safety equipment such as gloves, goggles, and a lab coat when handling chemicals. It is also recommended to perform the transfer in a fume hood to avoid inhaling any fumes.
By following these steps, you should be able to prepare the required amount of sulphuric acid for your experiment.
1.5L*2.30M= moles
Moles*98.079g/mole= mass of H2SO4
Mass of H2SO4/total=0.964 and mass of H2SO4/0.964= Y
Y/1.84= volume needed
But there is no such thing as a 1.5L volumetric flask. So you would need to perform this with a 2L volumetric flask and use 2L for your initial calculations. Just measure out only 1.5L to be used in your experiment. Add the volume needed and then add water. Shake well.