Grade 10 and 11 Science and Technology

Chapter summaries

Chapter 2 Summary



 

1 what is a Molecule?

• A molecule is a group of two or more chemically bonded atoms (p. 40).

• An ion is an atom that has become electrically charged by losing or gaining one or more electrons (p. 42).

2 PROPERTIES OF SOLUTIONS

• A solution is a homogeneous mixture whose component substances cannot be distinguished, even with the aid of a magnifying instrument (p. 51).

• An aqueous solution is a solution in which the solvent is water (p. 51).

• The concentration of a solution is the amount of solute in a given amount of solution (p. 52).

• The concentration in ppm (“parts per million”) is the number of parts of solute in a million parts of solution (p. 53).

• An electrolyte is a substance that, when dissolved in water, allows an electric current to flow through the solution (p. 55).

• The electrical conductivity of a solution is a measure of its ability to allow an electric current to flow through it (p. 55).

• Electrolytic dissociation is the separation of a dissolved compound into two ions of opposite charges (p. 55).

• An acid is a substance that releases H⁺ ions in an aqueous solution (p. 58).

• A base is a substance that releases OH^– ions in an aqueous solution (p. 59).

• A salt is a substance produced by the chemical bonding of a metallic ion and a nonmetallic ion (other than H⁺ and OH^– ions) (p. 59).

• pH is a property that distinguishes acidic, basic and neutral solutions (p. 60).