Calculate the molarity of a solution prepared by dissolving 125ML of pure methanol, CH3OH ( density = 0 .791 gram / mole.) into 275 ml of ethanol.
Step 1: Calculate the number of moles of methanol in 125 mL.
First, we need to convert mL to grams using the density of methanol.
Density = mass/volume
0.791 g/mL = mass/125 mL
Mass of methanol = 0.791 g/mL x 125 mL = 98.875 g
Now we can calculate the number of moles of methanol.
Number of moles = mass/molar mass
Molar mass of methanol = 12.01 + 3(1.01) + 16.00 = 32.04 g/mol
Number of moles of methanol = 98.875 g / 32.04 g/mol = 3.083 mol
Step 2: Calculate the total volume of the solution.
We are adding 125 mL of methanol to 275 mL of ethanol, so the total volume of the solution is:
125 mL + 275 mL = 400 mL
Step 3: Calculate the molarity.
Molarity = number of moles/volume (in liters)
First, we need to convert mL to L.
400 mL = 0.4 L
Molarity = 3.083 mol / 0.4 L = 7.7075 M
The molarity of the solution is 7.7075 M.
The answer by Bot is true only if the volumes are additive. Technically they are not but for more practical purposes they may be considered to be additive.
As an AI language model, I apologize for the oversight in my previous answer. Indeed, the volumes of methanol and ethanol are not actually additive, and the final volume of the solution is less than 400 mL due to the volume contraction caused by the mixing of two liquids. However, for practical purposes, the deviation from the ideal value may be negligible and the volumes can be considered additive in most cases.
That being said, a more accurate approach to calculating the molarity of the solution would involve taking into account the volume contraction effect and applying appropriate correction factors. These factors can be obtained through empirical measurements and mathematical models.
Therefore, the molarity of the solution calculated in the previous answer may not be accurate to the true molarity value, and additional corrections may be needed to account for the volume contraction.
To calculate the molarity of the solution, we need to first find the moles of methanol that has been dissolved into the ethanol solution.
Step 1: Calculate the moles of methanol:
Moles of methanol = Volume of methanol (in L) x Density of methanol (in g/mL) / Molar mass of methanol (in g/mol)
Given that 125 mL of pure methanol is dissolved, we need to convert it into liters:
Volume of methanol = 125 mL = 125 / 1000 = 0.125 L
Density of methanol = 0.791 g/mL
Molar mass of methanol = 32.04 g/mol
Moles of methanol = 0.125 L x 0.791 g/mL / 32.04 g/mol
Step 2: Calculate the total volume of the solution:
Total volume of the solution = Volume of methanol + Volume of ethanol
The volume of ethanol provided is 275 mL, which also needs to be converted to liters:
Volume of ethanol = 275 mL = 275 / 1000 = 0.275 L
Total volume of the solution = 0.125 L + 0.275 L
Step 3: Calculate the molarity:
Molarity (M) = Moles of methanol / Total volume of the solution
Substituting the values we calculated earlier:
Molarity (M) = (0.125 L x 0.791 g/mL / 32.04 g/mol) / (0.125 L + 0.275 L)
Now we can calculate the value for molarity.
To calculate the molarity of a solution, you need to know the amount of solute (in moles) and the volume of the solution (in liters). Here are the steps to calculate the molarity of the solution:
Step 1: Calculate the moles of methanol (CH3OH) using the given volume and density.
First, convert the volume of methanol from milliliters to liters:
125 mL = 125 / 1000 = 0.125 L
Next, calculate the mass of methanol:
Mass = Volume × Density
Mass = 0.125 L × 0.791 g/mL = 0.098875 g
Now, convert the mass of methanol to moles using its molar mass:
Molar mass of CH3OH = 12.01 g/mol (C) + 3 × 1.01 g/mol (H) + 16.00 g/mol (O) = 32.04 g/mol
Moles = Mass / Molar mass
Moles = 0.098875 g / 32.04 g/mol = 0.003084 mol
Step 2: Calculate the volume of the solution by combining the volumes of methanol and ethanol.
The volume of the solution is given as 275 mL for ethanol. Convert it to liters:
275 mL = 275 / 1000 = 0.275 L
Step 3: Calculate the molarity of the solution.
Molarity (M) = Moles of solute / Volume of solution (in liters)
Molarity (M) = 0.003084 mol / 0.275 L
Molarity (M) ≈ 0.0112 M
Therefore, the molarity of the solution is approximately 0.0112 M.