Q. When a ray of light passes through a solution, it is not visible. Explain.
Define an alloy? Why an alloy is considered as a mixture?
Ans. (a) An alloy is a homogeneous mixture of two or more metals or a metal and non-metal and cannot be separated into their components by physical methods.
(b) An alloy is considered as a mixture because it shows the properties of its constituents and can have variable composition.
For example,
brass is a mixture of approximately 30% zinc and 70% copper.
Concentration of a solution: The concentration of a solution is the amount of solute present in a given amount (mass or volume) of solution, or the amount of solute dissolved in a given mass or volume of a solvent.
Concentration of solution = Amount of solute / Amount of solution Or Amount of solute/Amount of solvent.
Expressing the Concentration of a Solution: The concentration of a solution is expressed as the amount of the solute present in a given amount of the solvent or solution. It is normally expressed as mass percent or as volume percent.
Mass Percent
Mass percent of a solution may be defined as: the number of parts by mass of one component (solute or solvent) per 100 parts by mass of the solution.
Volume Percent
Volume percent of a solution may be defined as: the number of parts by volume of one component (solute or solvent) per 100 parts by volume of the solution.
Example: A solution contains 40g of common salt in 320 g of water. Calculate the concentration in terms of mass by mass percentage of the solution.
Ans. Mass of solute (salt) = 40g, Mass of solvent (water) = 320g
We know, Mass of solution = Mass of solute + Mass of solvent = 40 g +320 g = 360 g
Mass percentage of solution
