Question

entropy is positive for reaction? *
2 points
Ag+ + CH- ---> AgCl
20 + CO2 ---> CaCo3
303 ---> 2 S02 + 02
4 AI + 3 02 --> 2 A1203​

Answer 1

Answer:

4 Al + 3 O2 → 2 Al2O3

Explanation:

Example 3

Balance this redox reaction by inspection.

SO2 + O2 → SO3

Solution

There is one S atom on both sides of the equation, so the sulfur is balanced. However, the reactant side has four O atoms while the product side has three. Clearly we need more O atoms on the product side, so let us start by including the coefficient 2 on the SO3:

SO2 + O2 → 2 SO3

This now gives us six O atoms on the product side, and it also imbalances the S atoms. We can balance both the elements by adding coefficient 2 on the SO2 on the reactant side:

2 SO2 + O2 → 2 SO3

This gives us two S atoms on both sides and a total of six O atoms on both sides of the chemical equation. This redox reaction is now balanced.

Test Yourself

Balance this redox reaction by inspection.

Al + O2 → Al2O3