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Weight Percent to Molarity Formula:
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The weight percent to molarity conversion formula calculates the molar concentration of a solution from its weight percentage, density, and molecular weight. This conversion is essential in chemistry for preparing solutions with precise concentrations.
The calculator uses the formula:
Where:
Explanation: The formula converts mass-based concentration to molar concentration by accounting for the solution's density and the solute's molecular weight.
Details: Accurate molarity calculation is crucial for preparing standard solutions, conducting chemical reactions, and performing quantitative analysis in laboratory settings.
Tips: Enter weight percentage in %, density in g/mL, and molecular weight in g/mol. All values must be positive numbers greater than zero.
Q1: Why multiply by 10 in the formula?
A: The factor of 10 converts weight percentage (per 100 parts) to a decimal fraction and adjusts units from g/100mL to g/L for molarity calculation.
Q2: When is this conversion most useful?
A: This conversion is particularly useful when working with concentrated stock solutions labeled by weight percentage that need to be diluted to specific molar concentrations.
Q3: What are typical density values for common solutions?
A: Density varies significantly. For example: water ≈1.0 g/mL, concentrated HCl ≈1.18 g/mL, concentrated H₂SO₄ ≈1.84 g/mL.
Q4: Are there limitations to this formula?
A: The formula assumes ideal behavior and may have slight inaccuracies for very concentrated solutions or solutions with significant volume changes upon mixing.
Q5: How does temperature affect the calculation?
A: Density is temperature-dependent, so use density values measured at the same temperature as your experimental conditions for accurate results.