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Atom Inventory

Atom Inventory. The language of change (Part 1). Find a less dangerous reaction to perform. ChemCatalyst. Below is a chemical “sentence” describing the formation of a very toxic substance, hydrogen cyanide. NaCN (s) + HCl (aq)  NaCl (aq) + HCN (g)

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Atom Inventory

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  1. Atom Inventory The language of change (Part 1)

  2. Find a less dangerous reaction to perform

  3. ChemCatalyst • Below is a chemical “sentence” describing the formation of a very toxic substance, hydrogen cyanide. • NaCN (s) + HCl (aq)  NaCl (aq) + HCN (g) • What kinds of information does this chemical notation contain? List at least four pieces of information contained in this chemical notation. Unit IV • Investigation II-X

  4. The Big Question • How do chemists describe chemical reactions, and what kinds of evidence do they look for to verify that their descriptions are correct? Unit IV • Investigation II-X

  5. You will be able to: • Identify the different components of a chemical equation and use that information to predict the outcome of the reaction it represents. Unit IV • Investigation II-X

  6. Notes • The previous chemical “sentence” is called a chemical equation. A chemical equation describes change. (cont.) Unit IV • Investigation II-X

  7. Notes(cont.) • The substances you start with before the change takes place are on the left side of the arrow. If there is more than one substance and they react with one another, they are called reactants. • The substances you end up with after the change takes place are on the right side of the arrow. They are often referred to as products. Unit IV • Investigation II-X

  8. HCl(aq) + NaHCO3(aq) NaCl(aq) + H2O (l)+ CO2(g)

  9. Meaning for each symbol in equation (cont.) Unit IV • Investigation II-X

  10. What would expect when you observe this reaction?

  11. Making Sense • Describe how a chemical equation keeps track of a chemical reaction. Unit IV • Investigation II-X

  12. Check-In • Consider the following reaction between sodium cyanide and a solution of hydrochloric acid. • NaCN (s) + HCl (aq)  NaCl (aq) + HCN (g) • Describe in detail what you would observe if you carried out this reaction. • Describe the products that you would have. Unit IV • Investigation II-X

  13. Wrap-Up • Chemical equations help chemists keep track of the substances involved in chemical and physical changes. • Chemical equations indicate the reactants and products of chemical reactions. Unit IV • Investigation II-X

  14. Atom inventory lab Part 2 Making Predictions

  15. ChemCatalyst • Consider the following reaction: • AgNO3 (aq) + KCl (aq)  KNO3(aq) + AgCl(s) • What do you expect to observe if you carried out the reaction? • Translate the above chemical equation into writing, describing what is taking place. Unit IV • Investigation II-X

  16. The Big Question • How do chemists predict the products of reactions and write the chemical reactions they represent? Unit IV • Investigation II-X

  17. You will be able to: • Use chemical reactions to predict expected real-world observations and use real-world observations to write the chemical reaction they represent. Unit IV • Investigation II-X

  18. Activity • Purpose: This lesson provides you with practice translating chemical equations.You will have the opportunity to check you predictions by completing the laboratory procedure associated with each equation. (cont.) Unit IV • Investigation II-X

  19. Time option • If we have time, we will perform the reactions in lab • If not discussion what should happen in groups

  20. (cont.) • Safety note: Do not touch the dry ice with your fingers. It causes burns. NaOH, Ca(OH)2, and NH4OH are caustic. Do not get them on your skin. In case of a spill, rinse with large amounts of water. Wear goggles. (cont.) Unit IV • Investigation II-X

  21. Unit IV • Investigation II-X

  22. Unit IV • Investigation II-X

  23. Unit IV • Investigation II-X

  24. Making Sense • Make a list of all the different types of things that you observed today that are associated with changes in matter. Unit IV • Investigation II-X

  25. Check-In • No Check-In exercise. Unit IV • Investigation II-X

  26. Wrap-Up • Chemical equations allow chemists to predict and track changes in matter. Unit IV • Investigation II-X

  27. Toxins Unit – Investigation II Lesson 3: Spare Change?

  28. ChemCatalyst • The following two equations both describe what happens when dry ice is placed in water: • CO2 (s)  CO2 (g) • CO2 (s) + H2O (l)  H2CO3 (aq) • What types of changes are described by these equations • Why do you think two equations are needed to describe what happens? Unit IV • Investigation II-X

  29. The Big Question • What are the differences between physical changes and chemical changes? Unit IV • Investigation II-X

  30. You will be able to: • Convert back and forth between chemical reaction notation and real world observations, and identify each change as either chemical or physical. Unit IV • Investigation II-X

  31. Notes • In a chemical equation describing a physical change, the chemical formulas do not change in going from reactants to products. However, the phase (s, l, & aq) does change. • In a chemical equation describing a chemical change, the chemical formulas of the reactants are different from those of the products. Unit IV • Investigation II-X

  32. Activity • Purpose: This activity provides you with practice distinguishing between physical and chemical changes using only the chemical equations. Unit IV • Investigation II-X

  33. Making Sense • Compare your observations for each reaction to the chemical equations. If you were asked to classify a reaction as a physical or chemical change, which would you prefer to have, a set of observations or chemical equations? Explain your thinking. Unit IV • Investigation II-X

  34. Notes • CaCl2 (s)  CaCl2 (aq) • CaCl2(s)  Ca2+(aq) + 2 Cl– (aq) Unit IV • Investigation II-X

  35. Check-In • Does the following chemical equation describe a physical change or a chemical change? Explain how you can tell. • C17H17O3N(s) + 2C4H6O3(l)  • C21H21O5N(s) + 2 C2H4O2(l) Unit IV • Investigation II-X

  36. Wrap-Up • Chemical changes involve the formation of new substances. Physical changes, such as phase changes, involve a change in form. • Chemical equations often provide more straightforward information about the type of change than mere observations. Unit IV • Investigation II-X

  37. Toxins Unit – Investigation II Lesson 4: Scrub the Air

  38. ChemCatalyst • In enclosed spaces such as on a space station or in a submarine, the breathing of the occupants causes a natural build up of carbon dioxide, CO2. Too much CO2 in the air is highly toxic. • List two ways to use chemical change to eliminate CO2 (g). Unit IV • Investigation II-X

  39. The Big Question • How does molecular bonding affect the outcome of chemical reactions? Unit IV • Investigation II-X

  40. You will be able to: • Classify certain chemical reactions as either combination or decomposition and predict the possible products when given specific reactants. Unit IV • Investigation II-X

  41. Notes • In a decomposition reaction, one reactant is broken apart into two or more substances. In a combination reaction, two or more substances combine to form a single product. • AB  A + B (decomposition) • A + B  AB (combination) (cont.) Unit IV • Investigation II-X

  42. (cont.) • CaCO3 CaO + Unit IV • Investigation II-X

  43. Activity • Purpose: You will compare different kinds of chemical reactions and learn the notation used to write chemical reactions. Unit IV • Investigation II-X

  44. Making Sense • Explain how you can predict the products of the decomposition of NaCl. • Explain how you can predict the product of the combination of carbon and hydrogen. Unit IV • Investigation II-X

  45. Check-In • List a possible product of the following combination reaction: • CH4 (g) + O2 (g)  Unit IV • Investigation II-X

  46. Wrap-Up • The substances in chemical reactions obey the bonding rules we have learned for ionic and covalent substances. • A decomposition reaction in one in which one reactant is broken apart into two or more substances. • A combination reaction is one in which two or more substances combine to form a single product. Unit IV • Investigation II-X

  47. Toxins Unit – Investigation II Lesson 5: Some Things Never Change

  48. ChemCatalyst • Consider the following reaction. • Na2CO3 (aq) + CaCl2 (aq)  • NaCl (aq) + CaCO3 (s) • Describe what you will observe when Na2CO3 (aq) and CaCl2 (aq) are mixed. • Will the mass increase, decrease, or stay the same after mixing? Explain. Unit IV • Investigation II-X

  49. The Big Question • What is the relationship between the mass of reactants and the mass of products of a chemical reaction? Unit IV • Investigation II-X

  50. You will be able to: • Explain the relationship between the mass of reactants and the mass of products of a chemical reaction. Unit IV • Investigation II-X

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