Define the following concepts
a. standard solution
b. mole
c. molar mass
Google is sure a big help with this kind of question.
http://en.wikipedia.org/wiki/Standard_solution
http://www.chemistry.co.nz/mole.htm
http://en.wikipedia.org/wiki/Molar_mass
For information on moles and molar have a look at:
cal.culate.it/moles
and
cal.culate.it/molarity
a. A standard solution refers to a solution of known concentration that is used as a reference in chemical analysis. It is prepared by precisely measuring the amount of a substance and dissolving it in a known volume of solvent. The concentration of a standard solution is usually determined through titration, where it is reacted with another solution with a known concentration to determine the unknown concentration.
To obtain a standard solution, follow these steps:
1. Accurately weigh the pure substance using a balance.
2. Transfer the weighed substance into a volumetric flask.
3. Dissolve the substance in the appropriate amount of solvent (usually water) to fill the flask to the specified volume.
4. Mix the solution thoroughly to ensure homogeneity.
b. A mole is a unit of measurement used in chemistry to count atoms, molecules, or other particles. It represents a specific number of particles, which is approximately 6.022 x 10^23, known as Avogadro's number. This number was determined experimentally and allows scientists to work with atoms and molecules on a macroscopic scale.
To calculate the number of moles, use the following equation:
Number of moles = Mass of the substance / Molar mass of the substance
c. Molar mass refers to the mass of one mole of a substance and is expressed in grams per mole (g/mol). It is calculated by summing up the atomic masses of all the atoms present in the chemical formula of the compound.
To determine the molar mass of a compound, follow these steps:
1. Write the chemical formula of the compound.
2. Determine the atomic mass of each element present in the formula using the periodic table.
3. Multiply the atomic mass of each element by the number of atoms of that element in the formula.
4. Sum up the masses of all the elements to obtain the molar mass.
For example, to find the molar mass of water (H2O):
- The atomic mass of hydrogen (H) is approximately 1 g/mol.
- The atomic mass of oxygen (O) is approximately 16 g/mol.
- Multiply the mass of hydrogen by 2 (since there are two hydrogen atoms in water) and the mass of oxygen by 1.
- Summing up the masses: (2 * 1) + (1 * 16) = 18 g/mol.
Therefore, the molar mass of water is 18 g/mol.