11 16 Is The Equation Balanced

Launch: 11/16   Grab your binder and immediately take a seat!

  Place homework (practice questions) on desk.

4Na + 4H2O 4NaOH + 2H2

3.  Which of the following identifies the coefficient for H2O in the above chemical equation?

a.  1

b.  2 c.  4 d.  8

Launch 11/16 5.  Which of the following identifies the correct

number of atoms in 3H2SO4? a.  3 H atoms, 3 S atoms, 3 O atoms b.  2 H atoms, 1 S atom, 4 O atoms c.  6 H atoms, 3 S atoms, 4 O atoms

d.  6 H atoms, 3 S atom, 12 O atoms

Launch: 11/16   Grab your binder and immediately take a seat!

  Place homework (practice questions) on desk.

HC2H3O2 + NaHCO3 NaC2H3O2 + H2CO3

2.  Which of the following correctly identifies all of the reactants in the above chemical equation.

a.  NaC2H3O2

b.  NaHCO3 c.  NaC2H3O2 and HC2H3O2 d.  HC2H3O2 and NaHCO3

Launch 11/16 5.  Which of the following identifies the correct

number of atoms in 3H2SO4? a.  3 H atoms, 3 S atoms, 3 O atoms b.  2 H atoms, 1 S atom, 4 O atoms c.  6 H atoms, 3 S atoms, 4 O atoms

d.  6 H atoms, 3 S atom, 12 O atoms

Launch: 11/16   Grab your binder and immediately take a seat!

  Place homework (practice questions) on desk.

1.  What are chemical equations?

a.  Representations of chemical reactions in which the reactants are listed to the left of a reaction arrow.

b.  Representations of chemical bonds in which 2 valence electrons are depicted by a straight line

c.  Representations of chemical reactions in which the. products are listed to the left of the reaction arrow.

d.  A way to show how reaction arrows turn into reactants.

Launch 11/16 HC2H3O2 + NaHCO3 NaC2H3O2 + H2CO3

2.  Which of the following correctly identifies all of the reactants in the above chemical equation.

a.  NaC2H3O2

b.  NaHCO3 c.  NaC2H3O2 and HC2H3O2 d.  HC2H3O2 and NaHCO3

Announcements   Unit #5: Chemical Reactions & Stoichiometry

  Class points end next week   Get your HW done   Be respectful

  Quiz on Friday!

Is the equation balanced? Mr. Heffner 11/16/09

  The Principle of Conservation of Matter states…   that, in a chemical reaction, atoms cannot be created

or destroyed

2H2 + O2 2H2O

What is conservation of matter?

The # of atoms on the reactants side

The # of atoms on the products side =

Is the equation balanced?

  Balanced: the # atoms is equal on both sides

  Unbalanced: the # of atoms is not equal on both sides

  Is the below equation balanced?   Count the # of atoms on both sides

2H2 + O2 2H2O

Example #1

4 X H 2 X O 4 X H 2 X O

Multiply the coefficients and

subscripts Yes, it is balanced!

Whiteboards   With a partner, determine whether or not the

equations are balanced.   First, re-write the equation on your whiteboard.   Then, count the atoms on each sides showing all of

your work!

  Finally, raise your hand to show Mr. Heffner when you have completed the problem.

  Do not go on to the next problem until you have been checked off!

Practice Questions   Practice question handouts

Exit Slip 1.  The “Principle of Conservation of Matter” states

that a.  in a chemical equation, the number of atoms on the

products side must equal then number of atoms on the reactants side.

b.  both of the reactants need to have the same number of atoms.

c.  both of the products need to have the same number of atoms.

d.  in a chemical reaction, matter can be created or destroyed.

Exit Slip 2.  Which of the following identifies the correct

number of atoms in 2H3PO4? a.  2 H atoms, 3 P atoms, 4 O atoms b.  6 H atoms, 2 P atom, 8 O atoms c.  6 H atoms, 3 P atoms, 4 O atoms

d.  6 H atoms, 3 P atom, 12 O atoms

Exit Slip Mg + 2H2O Mg(OH)2 + 2H2

3.  Is the above equation balanced? a.  No, because the number of H atoms is not equal

b.  No, because the number of O atoms is not equal c.  Yes, because the number of Mg atoms is not equal

d.  Yes, because there are equal numbers of atoms on both sides of the equation

Exit Slip 4.  Hydrogen gas (H2) and oxygen gas (O2) react to

form water (H2O). Which of these represents a properly balanced equation for this reaction?

a.  H2 + O2 H2O

b.  2H2 + 2O2 2H2O

c.  2H2 + O2 2H2O

d.  H2 + 2O2 2H2O

Exit Slip 5.  Which of the following is a balanced equation for

the combustion of ethanol (C2H6O)? a.  C2H6O + 3O2 CO2 + 2H2O b.  C2H6O + 3O2 2CO2 + 3H2O c.  C2H6O + O2 2CO2 + 3H2O

d.  C2H6O + 2O2 3CO2 + 2H2O

Homework   Finish practice question worksheet