1 / 18

Chemical Quantities

Chemical Quantities. 9.1: Information Given by Chemical Equations. Chemical Equations. are representations of a chemical change, in which atoms are rearranged. must be BALANCED to be useful. Balanced equations provide the relationship between the relative numbers of molecules. Example.

keon
Download Presentation

Chemical Quantities

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. Chemical Quantities 9.1: Information Given by Chemical Equations

  2. Chemical Equations • are representations of a chemical change, in which atoms are rearranged. • must be BALANCED to be useful. • Balanced equations provide the relationship between the relative numbers of molecules.

  3. Example • CO (g) + H2 (g) → CH3OH (l) Unbalanced • CO (g) +2H2 (g) → CH3OH (l) Balanced • Relative numbers 1:2:1 • 1 molecule of CO + 2 molecules of H2 yields 1 molecule of CH3OH • 1 mole of CO + 2 moles of H2 yields 1 mole of CH3OH

  4. CO (g) +2H2 (g) → CH3OH (l) • If you need 10 moles of CH3OH, how many moles of CO and H2 must react? • Relative numbers 1:2:1 • Increased from 1 to 10, so 10(1:2:1)=10:20:10 • Answer: 10 moles of CO and 20 moles of H2

  5. Mole–Mole Relationships • Remember only moles of elements or compounds can be compared, not grams. • Grams are used for measuring. • In order to compare moles in Unit Analysis, the mole ratio is used.

  6. What number of moles of oxygen gas is required to react with 7.4 moles of methane? Step 1: Balance Equation CH4 + O2 → CO2 + H2O __ x 4 H __ x 2 __ x 2 O __ x 2 +__ x 1 __ x 1 C __ x 1 CH4 + 2O2 → CO2 + 2H2O

  7. What number of moles of oxygen gas is required to react with 7.4 moles of methane? • Step 1: CH4 + 2O2 → CO2 + 2H2O • Step 2: Given/Goal • 7.4 moles of CH4 • Moles of O2 • Step 3: Know/Acquire • From Balanced Equation: 1mole CH4 = 2mole of O2

  8. What number of moles of oxygen gas is required to react with 7.4 moles of methane? • Step 1: Balance, Step 2: Given/Goal • Step 4: Unit Analysis • Step 3: Know/Acquire • From Balanced Equation: 1mole CH4 = 2mole of O2

  9. How many moles of carbon dioxide gas will be produced by reacting 2.6 moles of oxygen with excess methane? • Step 1: CH4 + 2O2 → CO2 + 2H2O • Step 2: Given/Goal • Step 4: Unit Analysis • Step 3: Know/Acquire • From Equation:

  10. How many moles of carbon dioxide gas will be produced by reacting 2.6 moles of oxygen with excess methane? • Step 1: CH4 + 2O2 → CO2 + 2H2O • Step 2: Given/Goal • 2.6 mol O2 • Mol CO2 • Step 4: Unit Analysis • Step 3: Know/Acquire • From Equation: • 2 mol O2 = 1mol CO2

  11. Chemical Quantities 9.3: Mass Calculations

  12. Mole–Mole Relationships • Recall: • ONLY moles can be compared through mole ratio from the balanced equation. • Mass (grams) is used to count by weighing.

  13. What mass of oxygen will be required to react exactly with 96.1g of propane? • C3H8 (g) + O2 → CO2 + H2O (unbalanced) • Step 1: BALANCE equation • C3H8 (g) + 5O2 → 3CO2 + 4H2O • Relative numbers: 1:5:3:4

  14. What mass of oxygen will be required to react exactly with 96.1g of propane? • Step 1: C3H8 (g) + 5O2 → 3CO2 + 4H2O • Step 2: Given/Goal • 96.1g C3H8 • Mass of oxygen (grams) • Step 3: Know/Acquire • From Periodic Table: • 1mole of O2 = 32.00grams • 1mole of C3H8 = 44.09grams • From Balanced Equation: 1mole C3H8 = 5mole of O2 ?mole C3H8 = ?mole of O2

  15. What mass of oxygen will be required to react exactly with 96.1g of propane? • Step 1: C3H8 (g) + 5O2 → 3CO2 + 4H2O • Step 3: Know/Acquire • 1mol O2 = 32.00g O2, 1mol C3H8 = 44.09g C3H8, 1mol C3H8 = 5mol O2 • Step 4: Unit Analysis

  16. Calculate the mass of carbon dioxide gas that is required to react with a solution containing 10.0 grams of sodium hydroxide. • NaOH(aq) + CO2(g) → Na2CO3(g) + H2O (l)

  17. Calculate the mass of carbon dioxide gas that is required to react with a solution containing 10.0 grams of sodium hydroxide. • Step 1:2NaOH(aq) + CO2(g) → Na2CO3(g) + H2O (l) • Step 2: Given/Goal • Step 3: Know/Acquire • From Periodic Table • From Balanced Equation • Step 4: Unit Analysis

  18. Calculate the mass of carbon dioxide gas that is required to react with a solution containing 10.0 grams of sodium hydroxide. • Step 1:2NaOH(aq) + CO2(g) → Na2CO3(g) + H2O (l) • Step 4: Unit Analysis • Step 2: Given/Goal • Step 3: Know/Acquire Periodic Table 1mol CO2= 44.0g 1mol NaOH=40.0g Balanced equation 2mol NaOH=1mol CO2

More Related