1 / 48

Chapter 7

Chapter 7. Solutions. Question. Why is 24K gold softer and more yellow than 10K or 18K? Red gold Cu/Au White gold Ni/Au Why can’t planes be made with Mg metal?. Other solutions. Do fillings ‘leak’? Solution of Hg, Ag, Zn Why add He to scuba tanks? Decrease partial pressure of N 2.

kyria
Télécharger la présentation

Chapter 7

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 7 Solutions

  2. Question • Why is 24K gold softer and more yellow than 10K or 18K? • Red gold Cu/Au • White gold Ni/Au • Why can’t planes be made with Mg metal?

  3. Other solutions • Do fillings ‘leak’? • Solution of Hg, Ag, Zn • Why add He to scuba tanks? • Decrease partial pressure of N2

  4. The Solution Process • Definitions: • Solution • Homogenous mixture of two or more elements and/or compounds • Air • 10 K gold • Pop

  5. The Solution Process • Definitions • Solvent • Component present in the greatest amount • Does the dissolving • Solute • Component present in the smallest amount • Is dissolved

  6. The Solution Process • Definitions • Miscible • Liquids that mix in all proportions • Suspension • Particles of a substance are mixed with a fluid but are not dissolved.

  7. The Solution Process • Definitions • Solvation • The interaction of solute and solvent • The process of dissolving • Hydration • Solvation when the solvent is water

  8. Gas in gas Gas in liquid Gas in solid Liquid in gas Liquid in liquid Liquid in solid Solid in gas Solid in liquid Solid in solid Air Carbonated water Pumice Fog Alcohol, pop, gas Tooth filling Smoke Sugar/salt water Rock, jewelry Nine Solutions

  9. Why does NaCl dissolve in water? • Ion-dipole interactions

  10. Why does Sugar dissolve in water? • Hydrogen bonding

  11. Other forces • Dipole-dipole bonding

  12. Other forces • London Dispersion

  13. What forces here?

  14. Solubility I • Saturated solution • A solution that holds the maximum amount of solute at a given temperature.

  15. Solubility II • Unsaturated • A solution that holds less than the maximum amount of solute at a given temperature.

  16. Solubility III • Supersaturated • A solution that holds more than the maximum amount of solute at a given temperature. • You need to know the solubility rules!

  17. Concentration • Generally: • Amount of solute/amount of solution

  18. Concentration • % Composition • w/w • v/v • w/v • Molarity

  19. % w/w - preparation • Convert to 100. g • How would you prepare 200. g of a 5.50% w/w solution of sugar?

  20. % w/w - mass • How many grams of phenol are in 2.5 g of a 0.20% w/w solution?

  21. % w/w – volume • How many grams of 6.30% w/w solution of CaCl2 are needed to obtain 27.6 g of CaCl2?

  22. Molarity • Always: moles solute Liters of solution

  23. Problem • What is the molarity of a solution that has 5.00 moles of NaCl dissolved to make 2.40 L of solution?

  24. Problem 2 • What is the molarity of a solution in which 43.44 grams of magnesium sulfate have been dissolved to make 0.600 L of solution?

  25. Problem 3 • How many grams of potassium nitrate are in 45.00 mL of a 0.500 M solution?

  26. Problem 4 • How would you make 600.00 mL of a 2.30 M solution of sulfuric acid?

  27. Solubility • Solubility of solids in liquids • Defined as whether a compound will dissolve in a solvent

  28. Saturated Solutions • At equilibrium • Some solid to aqueous • Some aqueous to solid • Floating golf ball

  29. Insolubility • A compound that will not dissolve in water is insoluble • See solubility rules • Use for reactions

  30. Practice • Lead nitrate solution is added to a solution of potassium iodide to form ______ and ______ • Identify the products and reactants as solid, liquid, aqueous, or gas

  31. Net Ionic Reaction • Rules: • Any (aq) can be written as an ion • Write the ionic equation • Leave any (s), (l), or (s) as a compound • Eliminate all ions that are the same

  32. Net Ionic Reaction? • Methane, CH4 is burned in oxygen gas

  33. Practice • Copper metal is added to a solution of silver nitrate to form _____ and ____.

  34. Practice • Calcium chloride solution is added to a solution of sodium phosphate

  35. The Chemical Equation • In a chemical reaction atoms are neither created nor destroyed. All atoms present in the reactants must also be present in the products. • Reactants: substances entering a reactions • Products: substances formed in a reaction • Reactions involve change, rearrangement, etc. of compounds but NOT of individual atoms

  36. The Chemical Equation • Conditions required to carry out the reaction sometimes included • Show heat is produced, etc. • Physical state of substances often included • (s) = solid • (l) = liquid • (g) = gas • (aq) = aqueous solution (substance dissolved in water)

  37. Writing and Balancing Equations • Equations must be BALANCED • Same number of each kind of atom on each side of the reaction • NEVER CHANGE FORMULAS – just change coefficients • Steps to follow: • Write a word equation for the reaction • Write the unbalanced (skeleton) equation

  38. Writing and Balancing Equations • Balance the equation • Count and compare the number of atoms of each element on each side of the equation • Balance each element, one at a time, by placing whole numbers (coefficients) in front of the formulas • Check all other elements and make adjustments as needed • Do a final check – all atoms should be balanced • Use smallest whole numbers

  39. Writing and Balancing Equations • Balance the following: Mg + N2 Mg3N2 AgNO3 + Cu  Cu(NO3)2 + Ag CaCO3  CaO + CO2 NH3 + HCl  NH4Cl 3 2 2

  40. What Information Does an Equation Tell Us? • What the reactants are and what the products are • The formulas of the reactants and products • The number of molecules or formula units of reactants and products in the reaction • The number of atoms of each element involved in the reaction • The number of moles of each substance

  41. Types of Chemical Equations • Reactions are classified based on how atoms or groups of atoms are rearranged during the reaction • Book lists 4 types • I want you to know 5 types • Synthesis (combination) • Decomposition • Single-Replacement (single-displacement) • Double-Replacement • Combustion (this is the one not covered in your book)

  42. Synthesis (Combination) Reaction • Two (or more) substances combine to form a new compound A + X  AX A and X are both elements or compunds AX is a new compound formed ** Only ONE product***

  43. Decomposition Reaction • A single compound reacts to give two or more substances • Usually requires heat and/or a catalyst AX  A + X

  44. Single-Replacement Reaction • An element reacts with a compound displacing an element from it A + BX  AX + B Y + BX  BY + X • If A is a metal, A will replace B to form AX, provided A is a more reactive metal than B • If Y is a halogen, it will replace X to form BY, provided Y is a more reactive halogen than C • Activity series can help make predictions

  45. Double-Replacement Reaction • Appears to involve the exchange of parts of the reactions • Ions of two compounds exchange places in an aqueous solution to form 2 new compounds • A precipitate (an insoluble solid compound formed during a reaction in solution) is often formed • Heat may be produced • Gas bubbles may be produced AX + BY  AY + BX

  46. Combustion Reactions • A reaction of a substance with oxygen, usually with the rapid release of heat to produce a flame • Organic compounds (with carbon) usually produce CO2 • If a compound contains hydrogen, water is a product • Hydrocarbon or compound + O2 CO2 + H2O • C3H8(g) + O2(g) CO2(g)+ H2O(l)

  47. 5 Types of Reactions • Identify each: • AX + BY  AY + BX • A + B  AB • A + BX  AX + B • AX  A + X • Hydrocarbon + O2  CO2 + H2O Double-Replacement Synthesis (Combination) Single-Replacement Decomposition Combustion

  48. Review • Gas laws • IM Forces • Concentration • Solubility • Net ionic reactions

More Related