Daily science pg 74
This presentation is the property of its rightful owner.
Sponsored Links
1 / 10

Daily Science pg. 74 PowerPoint PPT Presentation


  • 98 Views
  • Uploaded on
  • Presentation posted in: General

Daily Science pg. 74. How many atoms are in 3.6 mol of calcium? How many moles are in 1.45 x 10 24 atoms of sodium? What is the molar mass of K 2 SO 4 ? How many grams of CO are in 2.9 moles? How many moles is 236 g of NaOH ? What is the mass of 7.6 x 10 23 atoms of KF?

Download Presentation

Daily Science pg. 74

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Daily science pg 74

Daily Sciencepg. 74

  • How many atoms are in 3.6 mol of calcium?

  • How many moles are in 1.45 x 1024 atoms of sodium?

  • What is the molar mass of K2SO4?

  • How many grams of CO are in 2.9 moles?

  • How many moles is 236 g of NaOH?

  • What is the mass of 7.6 x 1023 atoms of KF?

  • How many atoms are in 192 g of MgCl2?


Empirical and molecular formulas

Empirical and mOlecular Formulas

Pg. 73


Determining moles in a compound

Determining moles in a compound

  • Formulas tell us ratios of the number of atoms in the compound

    • Ex. Freon is CCl2F2

    • There is 1 C, 2 Cl, and 2 F

  • We can figure out how many moles of one element there are in a given compound.

  • Moles of compound x # of atoms of element

    1 mole of compound


Daily science pg 74

Ex.

  • How many moles of F are in 5.50 moles of CCl2F2?

  • Calculate the number of moles of each element in 1.25 moles of C6H12O6.


Percent composition

Percent composition

  • First, find the molar mass of the compound

  • Multiply the mass of one element by its subscript

  • Divide the mass of one element by the total mass in the compound

  • Multiply by 100

  • Ex. H2O


Daily science pg 74

Ex.

  • Determine the percent by mass of each element in the compound CaCl2.


Empirical formulas

Empirical Formulas

  • Empirical formula = the formula with the smallest whole number ratio of the elements

  • If you know the percent composition of the element, divide the amount of that element by its molar mass.

  • This tells you # moles of that element.

  • If it is written as a percent, assume there are 100 g of the compound

  • If the numbers aren’t whole numbers, divide by the smaller value

  • If the numbers still aren’t whole numbers, multiply by the smallest factor that will make them whole


Daily science pg 74

Ex.

  • Compound with 40.05% S and 59.95% O

  • Determine the empirical formula for methyl acetate which has the following chemical make up: 48.64% C, 8.16% H, and 43.20% O.


Molecular formulas

Molecular formulas

  • Sometimes the empirical formula is the same for two different compounds

  • When that happens, you take the experimentally determined molar mass of the compound and divide it by the mass of the empirical formula

  • This gives you a whole number (n) that must be multiplied into the empirical formula


Daily science pg 74

Ex.

  • Succinic acid is composed of 40.68% C, 5.08% H and 54.24% oxygen and has a molar mass of 118.1 g/mol. Determine the empirical and molecular formulas for succinic acid.


  • Login