Chemical Reactions

Unit 7

1

Chemical Equations

2

Combustion ReactionsA substance reacts with O2 (typically with the help of a flame)

2 C4H10 + 13 O2 8 CO2 + 10 H2O

The coefficients in chemical reactions can be interpreted as moles

2 moles of C4H10 react to form 8 moles of CO2

Conversion Factor!

Chemical Equations

3

2 C4H10 + 13 O2 8 CO2 + 10 H2O

26 g of C4H10 is combusted.

How much water is formed (expressed in g)

How much carbon dioxide is formed (expressed in g)

Chemical Equations

4

2 C4H10 + 13 O2 8 CO2 + 10 H2O

26 g of C4H10 is combusted.

How much O2 was consumed in the reaction?

Is mass conserved? (does the mass of products = mass of reactants?

Chemical Equations

5

Sulfur dioxide (an environmental pollutant that leads to acid rain) is produced when sulfur containing fossil fuels are combusted. An example of this process is

the unbalanced equation below:

ZnS (s) + O2 (g) ZnO (S) + SO2 (g)

How much oxygen (in grams) is needed to completely react with 8.00 g of ZnS.

Chemical Equations

6

Sulfuric acid dissolves many metals. A product of this reaction is SO2, the hazardous gas discussed in the previous example.

Cu(s) + H2SO4(aq) CuSO4(aq) + H2O(l) + SO2(g)

How much SO2 (in grams) can be produced from 18.00 g of Cu?

How much sulfuric acid (in grams) is needed?