Section 8.1 Describing Chemical Change - CLK Schools

Chapter 8 Chemical Reactions

Adapted from notes by Stephen Cotton

1

Section 8.1 Describing Chemical Change

O OBJECTIVES: ? Write equations describing chemical reactions, using appropriate symbols ? Write balanced chemical equations, when given the names or formulas of the reactants and products in a chemical reaction.

2

Chemical Reactions

O Reactants ? O Products ? O Reactants

3

Symbols in Equations

O Arrow separates reactants from products.

O (s) = O (g) = O (l) = O (aq) =

4

Chemical Reactions

O Atoms

created or destroyed...

atoms are only rearranged.

O Chemical rxns/eqns follow the . .

O Sentence: Hydrogen gas and oxygen gas combine to form water.

O Word Eqn:

O Skeletal Eqn:

O Balanced Eqn:

5

Symbols in Equations

, heat Pt

6

1

Catalyst

O Substance that

a

reaction without itself being

changed or used up by the

reaction... ex: enzymes.

7

Balancing Chemical Equations

O Change number of atoms with

.

ONEVER, EVER change

.

8

Convert to Equation Form

O Nitric acid dissolved in water reacts with solid sodium carbonate to form liquid water, carbon dioxide gas, and sodium nitrate dissolved in water.

9

Convert to Sentence Form

O Fe(s) + O2(g) Fe2O3(s)

10

Balancing Examples

O Mg + N2 Mg3N2 O AgNO3 + Cu Cu(NO3)2 + Ag

11

Balancing Examples

O A chunk of sodium is dropped into a beaker of water resulting in the production of a solution of sodium hydroxide and hydrogen gas.

12

2

Balancing Examples

O Water and carbon dioxide are produced when methane (CH4) reacts with oxygen.

13

Section 8.2 Types of Chemical Reactions

O OBJECTIVES: ? Identify a reaction as combination, decomposition, single-replacement, double-replacement, or combustion ? Predict the products of combination, decomposition, single-replacement, double-replacement, and combustion reactions.

14

#1 - Combination Reactions

O A + B ? AB O Ca + O2 O Sulfur trioxide and water react.

15

#2 - Decomposition Reactions

O AB ? A + B O NaCl ? O Dihydrogen carbonate

decomposes upon heating.

16

#3 - Single Replacement

O AX + B ? A + BX O Metals replace other metals (and

hydrogen) according to the Activity Series of Metals on pg. 217. O Zn + HCl O A small piece of sodium is dropped into a beaker of water and explodes.

17

#4 - Double Replacement

O AX + BY ? AY + BX O Reactants must be two ionic

compounds or acids. O Usually in aqueous solution O NaOH + FeCl3

O Calcium chloride is mixed with sodium hydroxide.

18

3

#5 ? Combustion (of a hydrocarbon)

O Means "add oxygen" O A compound composed of C and H

for sure (and maybe O) reacts with oxygen. O If the combustion is complete, the products will be CO2 and H2O. O If the combustion is incomplete, the products will be CO and H2O.

19

Examples

O (complete) C6H12O6 + O2 O (incomplete) CH4 + O2 O Butane is combusted... O If it doesn't say, assume complete.

20

Section 8.3 Reactions in Aqueous Solution

O OBJECTIVES: ?Write and balance net ionic equations. ?Use solubility rules to predict the precipitate formed in double-replacement reactions.

21

Molecular, Complete Ionic, and Net Ionic Equations

O Solutions of silver nitrate and sodium chloride are mixed... using the solubility rules in T.8.3, pg.227, write the molecular, complete ionic, and net ionic equations for the reaction... include the physical state for all species.

22

Molecular, Complete Ionic, and Net Ionic Equations

O Solutions of iron(II) nitrate and aluminum chloride are mixed... using the solubility rules in T.8.3, pg.227, write the molecular, complete ionic, and net ionic equations for the reaction... include the physical state for all species.

23

4

 ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download