Balancing Equations and Air Composition

What is the balanced equation for the combustion of methane (CH4)?

• CH4 + 3 O2 -> 2 CO2 + 2 H2O

• CH4 + O2 -> C + 2 H2O

• CH4 + 2 O2 -> CO2 + 2 H2O

• CH4 + O2 -> CO + H2O

How many molecules of oxygen are needed to completely burn one molecule of propane (C3H8)?

• 3

• 4

• 6

• 5

What is the primary gas found in the Earth's atmosphere?

• Oxygen

• Helium

• Nitrogen

• Carbon Dioxide

What is the chemical formula for carbon dioxide?

• CO3

• CO

• CO2

• C2O

How do you balance the equation: H2 + O2 → H2O?

• 2 H2 + 2 O2 → 2 H2O

• 2 H2 + O2 → 2 H2O

• H2 + O2 → 2 H2O

• H2 + O2 → H2O

What percentage of the air is made up of nitrogen?

• 90%

• 78%

• 85%

• 72%

What is the balanced equation for the reaction of hydrogen and oxygen to form water?

• 2 H2 + 2 O2 -> 2 H2O

• 2 H2 + O2 -> 2 H2O

• H2 + 2 O2 -> 2 H2O

• H2 + O2 -> H2O

Which gas is produced when fossil fuels are burned?

• Carbon dioxide (CO2)

• Oxygen (O2)

• Nitrogen (N2)

• Methane (CH4)

What is the main component of air that supports combustion?

• Oxygen

• Carbon Dioxide

• Hydrogen

• Nitrogen

How do you determine the number of atoms in a balanced chemical equation?

• Count only the atoms in the reactants side of the equation.

• Add the coefficients of the reactants and products together.

• Count the total number of each type of atom on both sides of the balanced equation.

• Multiply the number of molecules by their respective weights.