How do you convert 300 nM (nanomolar) to molarity? And to a percentage? Maybe these conversions won’t work, but I have to convert this number into two different units.
The correct answer and explanation is:
Correct Answer:
- 300 nM (nanomolar) to molarity:
300 nM = 3.0 × 10⁻⁷ M - 300 nM to percentage (%):
300 nM ≈ 0.0000018%, assuming an aqueous solution and using water’s density.
Explanation (Approx. 300 words):
1. Converting 300 nM to Molarity (M):
Molarity (M) is the number of moles of solute per liter of solution. The prefix “nano-” means 10⁻⁹, so: 300 nM=300×10−9 M=3.0×10−7 M300\, \text{nM} = 300 \times 10^{-9}\, \text{M} = 3.0 \times 10^{-7}\, \text{M}
So, 300 nanomolar is 3.0 × 10⁻⁷ moles per liter.
2. Converting 300 nM to Percentage (%):
Percentage concentrations (especially weight/volume or w/v) are typically used in practical settings. For dilute aqueous solutions, we often assume:
- 1 L of water weighs ≈ 1000 g
- The molecular weight (MW) of the solute is needed, but if not specified, we use a hypothetical MW of 100 g/mol for estimation.
To convert molarity to mass percent: Mass of solute=Molarity×Molecular Weight\text{Mass of solute} = \text{Molarity} \times \text{Molecular Weight} =3.0×10−7 mol/L×100 g/mol=3.0×10−5 g/L= 3.0 \times 10^{-7}\, \text{mol/L} \times 100\, \text{g/mol} = 3.0 \times 10^{-5}\, \text{g/L}
To express as percent (g per 100 mL): 3.0×10−5 g in 1000 mL⇒3.0×10−6 g in 100 mL=0.000003%3.0 \times 10^{-5}\, \text{g in 1000 mL} \Rightarrow 3.0 \times 10^{-6}\, \text{g in 100 mL} = 0.000003\%
However, using a typical MW like 60 (e.g., urea or small molecule), the percent concentration becomes: 3.0×10−7×60=1.8×10−5 g/L=0.0000018%3.0 \times 10^{-7} \times 60 = 1.8 \times 10^{-5}\, \text{g/L} = 0.0000018\%
Important: The percentage value depends on the solute’s molecular weight. Without knowing the specific compound, you can only estimate.
Conclusion:
- 300 nM = 3.0 × 10⁻⁷ M (molarity)
- Approx. 0.0000018%, depending on molecular weight, when converted to percent concentration.