Carbon dioxide is a simple covalent compound, consisting of discrete molecules. The molecules are held together by weak intermolecular forces of attraction. Very little energy is needed to break these weak bonds, hence carbon dioxide has low melting point and boiling point.
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Total Internal Reflection and the Brilliance of Diamonds
A diamond is cut in such a way that the flat shape of the crown allows for the maximum number of light rays to either reflect off the crown or refract into the diamond.
The critical angle of diamonds will be small as the refractive index of diamond is high.
The shape and angle of the pavillion is such that most light rays falling on it will have an angle of incidence greater than the critical angle. This allows for total internal reflection to occur, causing light rays to reflect multiple times within the diamond, and leave the diamond through the crown.
The multiple light rays leaving the crown of the diamond makes it look more brilliant to an observer looking at the crown of the diamond.
Packets of Manufactured Powder
Number of Factors
Consider the factors of 2^6. There are 7 factors: 1, 2, 2^2, 2^3, ……, 2^6.
Similarly, for 3 there are 2 factors: 1, 3; and
similarly, for 643, there are 2 factors: 1, 643
So the total number of factors will be 7 x 2 x 2 – 2 (1 x 1 x 1 = 1, and 2^6 x 3 x 643 = 123456 need to be minus off) = 26 positive factors
A game between Alfred and Bertie
A tale of two dice
Describe a method of preparing silver chloride from the reaction of silver nitrate and dilute hydrochloric acid.
The silver chloride salt can be prepared using the precipitation method.
Add equal volumes of dilute hydrochloric acid to a beaker containing aqueous silver nitrate.
Stir the solution. A white precipitate of silver chloride is formed.
Filter the mixture to obtain silver chloride as the residue. Wash the residue with cold distilled water and dry between two pieces of filter paper.
Describe a method of preparing copper(II) sulfate from the reaction of copper(II) oxide and dilute sulfuric acid.
The copper(II) sulfate salt can be prepared using the filtration method.
Copper(II) oxide is added in excess to a fixed volume of dilute sulfuric acid.
Filter the mixture to remove the excess copper(II) oxide from the copper(II) sulfate solution.
The filtrate of copper(II) sulfate is then heated until saturated.
The saturated solution is allowed to cool so that crystals of copper(II) sulfate can be formed.
Filter the mixture to remove the excess water.
Wash the crystals with a little bit of cold distilled water and dry between two pieces of filter paper.
A tale of two dice again
p^2 + q^2
