Balancing the equation ensures the conservation of atoms on both sides. In this reaction, 2 molecules of hydrogen react with 1 molecule of oxygen to form 2 molecules of water.

Ionic compounds are formed by the transfer of electrons between metals and non-metals. Sodium chloride (NaCl) is the classic example of an ionic compound due to the transfer of an electron from sodium to chlorine.

Balancing by atoms, one methane molecule requires 2 oxygen molecules to provide enough oxygen atoms for the products. The correct coefficient for O2 is 2 when the equation is fully balanced.

In this reaction, two or more reactants combine to form a single product. This is a combination reaction, where elements directly combine to form a compound.

Covalent bonding typically occurs between non-metals where electrons are shared. Water (H2O) is a molecular compound formed by covalent bonds, unlike the ionic compounds listed.

Balancing this equation requires accounting for both iron and oxygen atoms. The correct balance is achieved with 4Fe + 3O2 -> 2Fe2O3, ensuring mass conservation.

CO2 is composed entirely of non-metals bonded covalently, making it a molecular compound. This compound does not form an ionic lattice structure.

A decomposition reaction involves a single compound breaking down into two or more simpler substances. The reaction 2KClO3 -> 2KCl + 3O2 clearly shows this breakdown.

Balancing hydrocarbon combustion reactions involves ensuring that carbon, hydrogen, and oxygen atoms are equal on both sides. The correctly balanced equation is C3H8 + 5O2 -> 3CO2 + 4H2O.

H2SO4 is a well-known strong acid, which dissociates in water to release H+ ions. Its acidic nature classifies it as an acid.

Zinc replaces hydrogen in hydrochloric acid, leading to the formation of zinc chloride and hydrogen gas. This displacement identifies the reaction as a single replacement reaction.

Proper balancing requires matching the number of atoms for each element on both sides. The balanced equation is 2Al + 6HCl -> 2AlCl3 + 3H2, which conserves mass and charge.

Polyatomic ions are groups of atoms that act as a single charged unit. Sodium nitrate (NaNO3) contains the nitrate ion (NO3❻), which is the polyatomic ion in this compound.

Oxygen almost always has an oxidation state of -2 in compounds (except in peroxides where it is -1). This constancy is key in balancing redox equations.

A synthesis reaction involves combining two or more reactants to form a single product. The reaction 2H2 + O2 -> 2H2O is a classic example of this type of reaction.

Balancing redox reactions in acidic medium requires adding H❺ ions and water molecules to balance oxygen and hydrogen atoms. The correct balanced reaction is MnO4❻ + 5Fe²❺ + 8H❺ -> Mn²❺ + 5Fe³❺ + 4H2O.

For the combustion of ethanol, the products are carbon dioxide and water. The balanced equation C2H5OH + 3O2 -> 2CO2 + 3H2O correctly accounts for all atoms on both sides.

The molar mass of KClO3 is approximately 122.55 g/mol with oxygen contributing about 48 g/mol. Dividing 48 by 122.55 and multiplying by 100 gives roughly 39.2% oxygen by mass.

Using stoichiometry, 10 moles of NH3 would require 12.5 moles of O2 (based on the 4:5 ratio). Since only 10 moles of O2 are available, O2 is the limiting reactant.

Ionic compounds typically feature high melting points and conduct electricity when dissolved or molten due to their free ions. In contrast, covalent compounds usually have low melting points and do not conduct electricity as they lack mobile charged particles.