A professor found that there are 109 drops of glacial acetic acid in 2.00 mL. Calculate the number of drops of glacial acetic acid, HC2H3O2 required to make 155 ml of 0.25 M acetic acid solution
Can anyone walk me through the steps and provide an answer. Ive tried everything and it always ends up incorrect!
The problem may well be the ambiguity in the molarity of glacial acetic acid. The molarity depends upon the density and percent composition.
mLacid x M acid = 155 x 0.25
IF we use 100% for the glacial acetic acid (I see 98-100% on the bottles) and density of 1.049 g/mL, then the calculated molarity of glacial acetic acid is 17.4M.)
So you need (155 x 0.25/17.4) = 2.227 mL which you would round to 2.23 mL.
Then 109 drops x (2.23 mL/2.00 mL) = ?
drops. You can adjust the numbers depending upon the molarity of the glacial acetic acid you are using.
Thank you so much!
To calculate the number of drops of glacial acetic acid required to make a 0.25 M acetic acid solution, we need to follow a step-by-step process. Here's how you can do it:
Step 1: Calculate the number of moles of acetic acid required.
To find the number of moles, we can use the formula:
moles = volume (in liters) * concentration (in M)
Given that the volume is 155 mL (or 0.155 L) and the concentration is 0.25 M, we can substitute these values into the formula:
moles = 0.155 L * 0.25 M
moles = 0.03875 mol
Step 2: Determine the molecular formula of glacial acetic acid.
Glacial acetic acid has the chemical formula of CH3COOH. To find the number of moles of glacial acetic acid needed, we need to consider the ratio of acetic acid (C2H4O2) to glacial acetic acid (CH3COOH). The ratio is 1:1, so the number of moles of glacial acetic acid is also 0.03875 mol.
Step 3: Convert moles to drops of glacial acetic acid.
To convert moles to drops, we need to know the number of drops of glacial acetic acid per mole. From the given information, we know that there are 109 drops of glacial acetic acid in 2.00 mL. We can use this conversion factor to calculate the number of drops:
drops = moles * (drops per mole)
drops = 0.03875 mol * (109 drops / 2.00 mL)
Step 4: Convert mL to drops.
To convert the volume from mL to drops, we need to know the number of drops per mL. From the given information, we have 109 drops per 2.00 mL. We can use this conversion factor to find the number of drops:
drops = 0.03875 mol * (109 drops / 2.00 mL) * (155 mL / 1)
By multiplying these values together, we can calculate the total number of drops required to make a 0.25 M acetic acid solution.
Let's calculate this:
drops = 0.03875 * (109/2) * 155
drops ≈ 0.03875 * 54.5 * 155
drops ≈ 331.65
So, the number of drops of glacial acetic acid required to make 155 mL of 0.25 M acetic acid solution is approximately 332 drops.
To calculate the number of drops of glacial acetic acid needed to make a certain volume and concentration of acetic acid solution, you need to follow these steps:
Step 1: Determine the molar mass of glacial acetic acid (HC2H3O2)
The molar mass of HC2H3O2 can be calculated by summing the atomic masses of each element in its chemical formula:
Molar mass (HC2H3O2) = (1 x atomic mass of H) + (2 x atomic mass of C) + (3 x atomic mass of H) + (2 x atomic mass of O)
Step 2: Calculate the number of moles of glacial acetic acid needed
The number of moles can be calculated using the given volume and concentration of the acetic acid solution:
moles = volume (in liters) x concentration (in moles per liter)
Step 3: Convert moles to drops
To convert moles to drops, you need to know the number of drops in a certain volume. In this case, you are given that there are 109 drops in 2.00 mL. Calculate the conversion factor (drops per mL) using the given information:
conversion factor = 109 drops / 2.00 mL
Step 4: Calculate the number of drops needed
Multiply the number of moles calculated in step 2 by the conversion factor obtained in step 3:
number of drops = moles x conversion factor
Now let's do the calculations:
Step 1: Determine the molar mass of HC2H3O2
Molar mass (HC2H3O2) = (1 x 1.01 g/mol) + (2 x 12.01 g/mol) + (3 x 1.01 g/mol) + (2 x 16.00 g/mol)
Molar mass (HC2H3O2) = 60.05 g/mol
Step 2: Calculate the number of moles of HC2H3O2 needed
moles = volume (in liters) x concentration (in moles per liter)
moles = 155 mL x (1 L / 1000 mL) x 0.25 mol/L
moles = 0.03875 mol
Step 3: Convert moles to drops
conversion factor = 109 drops / 2.00 mL
conversion factor = 54.5 drops/mL
Step 4: Calculate the number of drops needed
number of drops = moles x conversion factor
number of drops = 0.03875 mol x 54.5 drops/mL
number of drops = 2.1144 drops
Therefore, approximately 2.11 drops of glacial acetic acid are required to make 155 mL of 0.25 M acetic acid solution.
Note: It is important to keep in mind that the number of drops can vary based on factors such as the size and shape of the dropper used.