{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

L18a-c_Unit_7a-3_ALL[1]

# 023 x 1023 par9cles consider the water molecule h2o 1

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Every reac9on has a ﬁxed mole ra9o that can be used for STOICHIOMETRY calcula9ons Prac<ce Problem 1 Magnesium reacts with oxygen to produce magnesium oxide. If you have 3.2 moles of Mg, how many moles of O2 are required to completely react the Mg? Step 1: Step 2: 2Mg(s) + O2(g) ! 2MgO(s) Moles O2 = Moles Mg x ra9o (O2/Mg) = 3.2 x (1/2) = 1.6 moles of O2 Prac<ce Problem 2 C3H8 is an organic compound that reacts with oxygen to produce carbon dioxide and water. If 44.6 moles of C3H8 react, how many moles of carbon dioxide are formed? Step 1: C3H8 + 5O2 ! 3CO2 + 4 H2O Step 2: Moles CO2 = Moles C3H8 x ra9o (CO2/C3H8) = 44.6 x (3/1) = 133.8 moles of O2 Prac<ce Problem 3 Diphosphorous pentoxide is oien used as a drying reagent because it eﬀec<vely removes water by reac<ng with it in solu<on. If I react 1.87 moles of diphosphorous pentoxide with water to produce trihydrogen phosphate (aka phosphoric acid), how many moles of water are consumed in this reac<on? Step 1: P2O5 (s) + 3H2O (l) ! 2H3PO4 (aq) Step 2: Moles H2O = Moles P2O5 x ra9o (H2O/P2O5 ) = 1.87 x (3/1) = 5.61 moles of H2O But what is the MOLE? The Mole is a unit that represents a very very big number A number big enough to represent so many atoms that we can see them MACROSCOPICALLY 1 mole = 6.023 x 1023 par9cles This is called Avogadro’s number This is the SAME for all elements and compounds The MOLE also represents a speciﬁed mass of a substance 1 mole = speciﬁed # grams (MOLAR MASS ) Each element on the...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online