Chemistry- Penny

Chemistry- Penny

1. Solubility

   • Read Blackman: • Liquid-liquid solutions: pp 394-396 • Section 3.6 p 90 Do questions from Blackman listed on page 14 in the Tutorial Workbook.
   • solute + solvent → solution
     • Solution: homogeneous mixture of two or more substances, a solute and a solvent Solute: the substance present in the lesser amount in a solution Solvent: the substance present in the greater amount in a solution
   • Dissociation is the release of ions already present
   • Ions must be present to conduct electricity in solutions.
   • Ionic compounds: dissociate in water, releasing the ions that are present in the solid compound. These substances are electrolytes.
     • Polar molecules that dissolve by forming hydrogen bonds. No Ions
     • Polar molecules that dissolve by forming ions when reacting with water form ions. are electrolytes.
   • Solubility = Mass/100g of water maximum amount of solute that can dissolve
     • Solubility = Mass/100g of water maximum amount of solute that can dissolve
   • Hint: SNAP Sodium, Nitrates, Ammonium and Potassium salts are soluble
   • The solubility of most solids increases with an increase in temperature.
     • The solubility of gases decreases with an increase in temperature

2. Chemical Reactions

   • Do questions from Blackman listed on page 14 in the Tutorial Workbook. Read Blackman: • 3.1: Chemical equations (p72) • 3.2: Balancing chemical equations (p73-74)
   • Mass is always conserved in chemical reactions.
   • When two solutions are mixed, an insoluble substance sometimes forms. The solid is called a precipitate
   • When writing ionic equations: •if has (s), (l), or (g) always remain in the ionic equation. • those with (aq) beside them on both sides of the arroware spectator ions and can be omitted from the overall (net) ionic equation

3. Mole Concept

   • Do some of the Practice Questions for Lecture 10 on the LMS under my lecture notes. Read Blackman: section 3. 3: The mole 
   • A mole is the amount of substance that has the same number of particles as there are atoms in 12 g of carbon-12.
     • This number = 6.022 045 × 10^23 (Avogadro’s constant)
   • n = m/M

4. States of matter & Gas Law

   • Blackman 3.4, 6.1,6.2 Do practise questions for lecture 11 
   • Empirical formula – simplest whole number ratio of elements present in compound.
     • Find mass of all  Find Molar mass  Find no of mole  divide by the smallest amount (From 3)  round off to whole numbers  assign corresponding elements. 
     • Molecular formula – actual number of atoms of each element present in one molecule of the compound
   • Matter is anything occupying space and has mass
   • A gas: Uniformly fills any container mixes completely with any other gas is highly compressible exerts pressure on surroundings
     • Kinetic molecular theory of gas:  1. Gas molecules move in random, straight lines and collide with each other and container walls  2. It is assumed that no forces exist between ideal gas molecules  3. The volume of a gas molecule is negligible compared to the volume of the container 4. Collisions are elastic (Energy conserved)  5. The avg KE of molecules increases if Temp increases
     • 1 bar = 100kPa 1 atm = 101.325kPa
       • Temperature increases = Particles move faster, more collisions and pressure increases
         • Volume decreases = more collisions per unit vol, pressure increases
     • Boyle's Law: p1v1 = p2v2
       • Charles's law: v1T1 = v2T2
         • Avogadro's Law: v1/n1 = v2/n2

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