Chapter4 - 1 Chapter Four Chemical Reactions in Aqueous...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chemical Reactions in Aqueous Solutions Chapter Four Chapter Four
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Electric current is a flow of charged particles. One type of current is electrons flowing through a wire, from cathode (negative electrode) to anode (positive electrode). Conduction Illustrated Another type of current: anions and cations moving through a solution as shown here. Cations move to the cathode , anions move to the anode . Of course, an external source of potential (voltage) is required in either case!
Background image of page 2
3 Why do some solutions conduct electricity? An early hypothesis was that electricity produced ions in solution, and those ions allowed the electricity to flow. Arrhenius’s theory: Certain substances dissociate into cations and anions when dissolved in water. The ions already present in solution allow electricity to flow. Arrhenius’s Theory of Electrolytic Dissociation
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Electrolytes dissociate to produce ions. Electrolytic Properties of Aqueous Solutions The more the electrolyte dissociates, the more ions it produces.
Background image of page 4
5 Electrolyte – a solute that produces enough ions to make a solution an electrical conductor. A strong electrolyte dissociates completely. A strong electrolyte is present in solution almost exclusively as ions . Strong electrolyte solutions are good conductors. A nonelectrolyte does not dissociate. A nonelectrolyte is present in solution almost exclusively as molecules . Nonelectrolyte solutions do not conduct electricity. A weak electrolyte dissociates partially. Weak electrolyte solutions are poor conductors. Different weak electrolytes dissociate to different extents. Types of Electrolytes
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 Strong electrolytes include: – Strong acids (HCl, HBr, HI, HNO 3 , H 2 SO 4 , HClO 4 ) Strong bases (IA and IIA hydroxides) Most water-soluble ionic compounds Weak electrolytes include: Weak acids and weak bases A few ionic compounds Nonelectrolytes include: Most molecular compounds Most organic compounds (most of them are molecular) Is it a strong electrolyte, a weak electrolyte, or a nonelectrolyte? How do we tell whether an acid (or base) is weak ?
Background image of page 6
7 Identify each substance as a strong electrolyte, a weak electrolyte, or a nonelectrolyte. (a) HClO 4 (b) HNO 2 (c) KBr (d) LiOH (e) cyclohexane Is it a strong electrolyte, a weak electrolyte, or a nonelectrolyte?
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
• In 0.010 M Na 2 SO 4 : two moles of Na + ions are formed for each mole of Na 2 SO 4 in solution, so [Na + ] = 0.020 M. – one mole of SO 4 2– ion is formed for each mole of Na 2 SO 4 in solution, so [SO 4 2– ] = 0.010 M. An ion can have only one concentration in a solution, even if the ion has two or more sources. Calculating Ion Concentrations in
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 44

Chapter4 - 1 Chapter Four Chemical Reactions in Aqueous...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online