C 1 notes atom inventory balancing equations
This presentation is the property of its rightful owner.
Sponsored Links
1 / 14

C.1 Notes: Atom Inventory & Balancing Equations PowerPoint PPT Presentation


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

C.1 Notes: Atom Inventory & Balancing Equations. Reactants --> Products. #'s & types of atoms in Reactants. #'s & types of atoms in Products. =. Conservation. Atoms are FOREVER!!.

Download Presentation

C.1 Notes: Atom Inventory & Balancing Equations

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


C 1 notes atom inventory balancing equations

C.1 Notes: Atom Inventory& Balancing Equations

Reactants --> Products

Rev 6/3/04


Conservation

#'s & types of atoms

in Reactants

#'s & types of atoms

in Products

=

Conservation

Atoms are FOREVER!!

  • Law of Conservation of Matter—in a chemical reaction, matter can neither be created nor destroyed – just rearranged.

  • The numbers & kinds of atoms present in the products are the same as those in the reactants.

  • Balanced equations illustrate this law.


Atom inventory

O

O

O

H

H

H

H

H

H

Atom Inventory

  • List atoms in reactants and products under the arrow

  • Determine the number of each atom.

  • Subscripts—show a ratio of atoms to each other in a particular compound.

    H2O =‘s 2 hydrogens bonded to 1 oxygen

  • Subscripts are NEVER changed when balancing!

  • Coefficients—(#’s in front of compound) show how many of each compound is present. 2H2O =‘s 2 waters


C 1 notes atom inventory balancing equations

Example of Atom Inventory:

CH4 + 2 O2 CO2 + 2 H2O

ReactantsProducts

____ C____

____ H____

____ O____

1

1

4

4

4

4

What does it mean if there is no coefficient in front of the compound?

Is this equation balanced?

Yes!!!

It is an implied “1”!


Steps to balance

Steps to Balance

  • Do an atom inventory.

  • Balance by using coefficients to show multiple number of elements or compounds.

    (NEVER change subscripts to balance…is H2Othe same as H2O2?If so, would you like a big cold glass of hydrogen peroxide?!)

    (Coefficients only inserted in front of compound, never split compound or the ratio would D)

  • Recount both sides.


Example h 2 g o 2 g h 2 o l

Example:H2 (g) + O2 (g)  H2O (l)

2

2

  • Atom Inventory:

    Reactants Products

    2H2

    2O1

  • Insert coefficients to balance

    3. Double check to make sure it is all BALANCED!

4

4

2


C 1 notes atom inventory balancing equations

Balance

Al + O2 Al2O3

4

3

2

ReactantsProducts

____ Al____

____ O____

1

-- 4

-- 4

2

2

-- 6

-- 6

3

Do an atom inventory

No

Is this equation balanced?

Use coefficient to multiplyCOMPOUND with element in it by # that balances it.


Additional rules

Additional Rules

  • Polyatomic ions, (like NO3- and CO32-) that appear on both sides of equation should be balanced as units rather than balancing their atoms individually

  • AgNO3+ Cu ---> Cu(NO3)2 + Ag

  • Balance atoms in pure elements w/ no subscripts last

  • Recount all atoms one last time to be sure you are correct!

2

2


Balancing equations

Balancing Equations

  • For labs, demos, and whenever possible, indicate the states of each element or compound.

    • (s) solid (g) gas

    • (l) liquid (aq) aqueous

  • Diatomic Elements?

  • H O F Br I N Cl

  • Remember these elements need a subscript of 2 if in elemental state. If in compound then criss- cross charges to get subscripts


Practice

Practice

2 NaCl + H2SO4  Na2SO4 + 2 HCl

  • NaCl + H2SO4  Na2SO4 + HCl

  • BaF2 + Al(OH)3  Ba(OH)2 + AlF3

  • 3 BaF2 + 2 Al(OH)3  3 Ba(OH)2 + 2 AlF3

  • C2H6 + O2  CO2 + H2O

  • 2C2H6 + 7O2  4CO2 + 6H2O

(had to double everything to balance oxygen)


Balanced equations show proportions

Balanced Equations show Proportions

  • Coefficients show how many of each compound reacts with, or creates another substance.

  • Does that mean ONLY 2 hydrogen molecules will react with only 1 oxygen molecule?

  • NO!! Could be 250 H2 react with 125 O2


Example 2 h 2 g o 2 g 2 h 2 o l

Example:2 H2 (g) + O2 (g)  2 H2O (l)

  • 2 H2 molecules produce 2 H2O molecules

  • 1 O2 molecule produces 2 H2O molecules

  • 2 H2 molecules react with 1 O2 molecules


Example 2 h 2 g o 2 g 2 h 2 o l1

Example:2 H2 (g) + O2 (g)  2 H2O (l)

  • Does that mean ONLY 2 hydrogen molecules will react with only 1 oxygen molecule?

  • NO!! Could be 250 H2 react with 125 O2


Types of chemical reactions

Types of Chemical Reactions

Examples

A + B  AB

N2 + 3H2 2NH3

  • Synthesis

  • Decomposition

  • Single replacement (displacement)

  • Double replacement (displacement)

  • Combustion

H2O2  H2 + O2

AB  A + B

A + BC  AC + B

Zn + 2HCl  ZnCl2 + H2

A + BD BA + D

AB + CD  AD + CB

NaCl + AgNO3 NaNO3 + AgCl

CxHy + O2 CO2 + H2O

CH4 + 2O2 CO2 + 2H2O


  • Login