0.30 moles/liter 0.30 mmoles/liter 0.30 mmoles/ml 0.30 µmoles/m
The Correct Answer and Explanation is:
Correct Answer
The two equivalent concentrations are:
- 0.30 moles/liter
- 0.30 mmoles/ml
Explanation
Understanding and Comparing Concentration Units
In chemistry and biology, concentration is a fundamental property that describes the amount of a substance (solute) dissolved in a given volume of a solution. The standard international (SI) unit for concentration is moles per liter (mol/L), also known as molarity (M). However, for practical purposes in the laboratory, concentrations are often expressed using different metric prefixes for both the amount (moles) and the volume (liters). To accurately compare these values, one must convert them to a common unit.
The key to these conversions lies in understanding the relationships between the prefixes:
- Amount: 1 mole = 1,000 millimoles (mmoles) = 1,000,000 micromoles (µmoles)
- Volume: 1 liter (L) = 1,000 milliliters (ml)
Let’s analyze each expression by converting it to the base unit of moles per liter (mol/L) for a direct comparison.
- 0.30 moles/liter: This is our reference concentration. It is already in the base unit.
- 0.30 mmoles/liter: To convert this, we change millimoles to moles. Since 1 mole = 1000 mmoles, we divide by 1000.
- 0.30 mmoles/L × (1 mole / 1000 mmoles) = 0.00030 moles/liter
- 0.30 mmoles/ml: This requires converting both the numerator (mmoles to moles) and the denominator (ml to L).
- Numerator: 0.30 mmoles = 0.00030 moles
- Denominator: 1 ml = 0.001 L
- Concentration = (0.00030 moles) / (0.001 L) = 0.30 moles/liter
- Alternatively, notice that the conversion from milliliters to Liters (multiplying by 1000) and the conversion from millimoles to moles (dividing by 1000) mathematically cancel each other out, making the numerical value identical to that of mol/L.
- 0.30 µmoles/ml: We convert micromoles to moles and milliliters to liters. Since 1 mole = 1,000,000 µmoles, we divide by 1,000,000.
- 0.30 µmoles/ml × (1 mole / 1,000,000 µmoles) × (1000 ml / 1 L) = 0.00030 moles/liter
By comparing the final values, we can conclude that 0.30 moles/liter and 0.30 mmoles/ml represent the exact same concentration.thumb_upthumb_down
