Chapter_03-Stoichiometry

# Chapter_03-Stoichiometry - Chapter 3 Stoichiometry Chapter...

This preview shows pages 1–6. Sign up to view the full content.

Chapter 3. Stoichiometry Chapter 3. Stoichiometry Chemical Chemical equations equations 2H 2 + O 2 2H 2 O Chemical reaction Reactants Products Coefficient Example: burning of hydrogen in oxygen Chemical equation:

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Chapter 3. Stoichiometry Chapter 3. Stoichiometry Chemical Chemical equations equations Balancing chemical equations (simple cases) Balancing chemical equation means making the number of corresponding atoms equal from both sides. Example 1: burning of metane in oxygen: 1.CH 4 + O 2 CO 2 + H 2 O (unbalanced); 2.CH 4 + O 2 CO 2 + 2H 2 O (still unbalanced); 3.CH 4 + 2O 2 CO 2 + 2H 2 O (balanced). Result: One carbon, four hydrogen and four oxygen atoms are both among reactants (left side) and at products (right side). Example 2: oxydation of iron: 1.Fe + O 2 Fe 2 O 3 (unbalanced) 2.Fe + 3O 2 2Fe 2 O 3 (still unbalanced) 3.4Fe + 3O 2 2Fe 2 O 3 (balanced) Result: Four iron and six oxygen atoms at both sides. Hint: It is good idea to start balancing those elements that are contained in the fewest number of formulas.
Chapter 3. Stoichiometry Chapter 3. Stoichiometry Chemical Chemical equations equations Example: oxydation of butene by hydrogen peroxide 1.C 4 H 8 + H 2 O 2 CO 2 +H 2 O (unbalanced) 2.a*C 4 H 8 + b*H 2 O 2 c*CO 2 +d*H 2 O (balanced with unknown coefficients) Now we make several mathematical equations – balancing each element separately: For C: 4*a = c For H: 8*a + 2*b = 2*d For O: 2*b = 2*c + d …… Result: b=12*a; c=4*a; d=16*a; We arbitrary select the smallest coefficient a to be 1; Result of balancing: 3. C 4 H 8 + 12H 2 O 2 4CO 2 +16H 2 O (balanced) Balancing chemical equations (advanced)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Chapter 3. Stoichiometry Chapter 3. Stoichiometry Chemical Chemical equations equations 1. Cu 2 O + 2CO 2 2CuO + CO 2. 2C 6 H 6 + 2HNO 3 + O 2 2C 6 H 5 NO 3 + 2H 2 O 3. 3 H 2 + 2N 2 2N H 3 Which reactions are not balanced?
Chapter 3. Stoichiometry Chapter 3. Stoichiometry Chemical Chemical equations equations Possible states: Gas ( g ) Liquid ( lq ) Solid ( s ) Aqueous solution ( aq ) Indicating physical state in chemical equations Example: Precipitation of solid calcium carbonate: Na 2 CO 3 (aq) + CaCl 2 (aq) 2NaCl(aq) + CaCO 3 (s) Example: Release of carbon dioxide gas: Na 2 CO 3 ( aq

This preview has intentionally blurred sections. Sign up to view the full version.

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

## This note was uploaded on 01/02/2012 for the course CHEM 114 taught by Professor Sergeiaksyonov during the Fall '11 term at ASU.

### Page1 / 18

Chapter_03-Stoichiometry - Chapter 3 Stoichiometry Chapter...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online