Question

Of the balanced chemical equations below, which one most correctly represents a combustion reaction?
1.2 N2 + 3 H2 → 2 NH3
2.2 Mg + O2 → 2 MgO
3.2 CH4 + 4 O2 → 2 CO2 + 4 H2O
4.CaO + H2O → Ca (OH)2

Answer 1

Answer:

I think it is 4 one

I hope it help you☺☺

Answer 2

Answer:

A combustion reaction occurs when a reactant combines with oxygen, many times from the atmosphere, to produce oxides of all other elements as products; any nitrogen in the reactant is converted to elemental nitrogen, N2. Many reactants, called fuels, contain mostly carbon and hydrogen atoms, reacting with oxygen to produce CO2 and H2O. For example, the balanced chemical equation for the combustion of methane, CH4, is as follows:

CH4 + 2 O2 → CO2 + 2 H2O

Kerosene can be approximated with the formula C12H26, and its combustion equation is

2 C12H26 + 37 O2 → 24 CO2 + 26 H2O

Sometimes fuels contain oxygen atoms, which must be counted when balancing the chemical equation. One common fuel is ethanol, C2H5OH, whose combustion equation is

C2H5OH + 3 O2 → 2 CO2 + 3 H2O

If nitrogen is present in the original fuel, it is converted to N2, not to a nitrogen-oxygen compound. Thus, for the combustion of the fuel dinitroethylene, whose formula is C2H2N2O4, we have

2 C2H2N2O4 + O2 → 4 CO2 + 2 H2O + 2 N2

Example 10

Complete and balance each combustion equation.

the combustion of propane, C3H8

the combustion of ammonia, NH3

Solution

The products of the reaction are CO2 and H2O, so our unbalanced equation is

C3H8 + O2 → CO2 + H2O

Balancing (and you may have to go back and forth a few times to balance this), we get

C3H8 + 5 O2 → 3 CO2 + 4 H2O

The nitrogen atoms in ammonia will react to make N2, while the hydrogen atoms will react with O2 to make H2O:

NH3 + O2 → N2 + H2O

To balance this equation without fractions (which is the convention), we get

4 NH3 + 3 O2 → 2 N2 + 6 H2O

Test Yourself

Complete and balance the combustion equation for cyclopropanol, C3H6O.

Answer

C3H6O + 4 O2 → 3 CO2 + 3 H2O