Define
(a) millimole.
(b) molar mass.
(c) millimolar mass.
(d) parts per million.
The Correct Answer and Explanation is :
(a) Millimole:
A millimole (mmol) is a unit of amount of substance in the metric system. It represents one-thousandth (1/1000) of a mole. The mole (mol) is the base unit used in chemistry to express amounts of a chemical substance. The millimole is often used for more precise measurements in smaller quantities of substances.
1 millimole = ( 10^{-3} ) moles = 0.001 moles.
For example, if a solution has 5 millimoles of solute, it means there are 5 thousandths of a mole of the substance.
(b) Molar Mass:
Molar mass is the mass of one mole of a substance, typically measured in grams per mole (g/mol). It represents the total mass of all atoms in a molecule or formula unit of a compound, and it is the sum of the atomic masses of the elements present in the compound.
For example, the molar mass of water (H₂O) is calculated by adding the atomic masses of two hydrogen atoms and one oxygen atom:
- Hydrogen: 1.008 g/mol × 2 = 2.016 g/mol
- Oxygen: 16.00 g/mol
Thus, the molar mass of H₂O is 18.016 g/mol.
(c) Millimolar Mass:
Millimolar mass refers to the mass of one millimole (1 mmol) of a substance. In this case, the term “millimolar” refers to the concentration of a substance in a solution. When considering the “millimolar mass,” it’s typically about the mass corresponding to 1 millimole of a substance.
For example, if the molar mass of a substance is 100 g/mol, the millimolar mass is:
1 millimole = 0.001 moles,
so the millimolar mass is 100 mg per millimole (mg/mmol).
(d) Parts Per Million (ppm):
Parts per million (ppm) is a unit used to measure the concentration of one substance in a solution, typically referring to very small concentrations. It denotes the ratio of the amount of solute to one million parts of solution. This can also be written as mg/L (milligrams per liter) for water or aqueous solutions.
1 ppm = 1 mg of solute per liter of solution.
For example, if a solution has a concentration of 10 ppm of a contaminant, it means there are 10 milligrams of the contaminant in one liter of solution.
These definitions and explanations are important for understanding how substances are measured, especially in chemistry, biology, and environmental science. Let’s generate an image that visually represents these concepts.
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