Which of the following statements describe the information that can be gained from a balanced chemical equation? select all that apply.
Question: Which of the following statements describe the information that can be gained from a balanced chemical equation? select all that apply.
The following statements describe the information that can be gained from a balanced chemical equation:
- The relative quantities of reactants and products: The coefficients in front of the chemical formulas in a balanced chemical equation indicate the relative quantities of reactants and products that are required for a complete reaction. For example, the balanced chemical equation for the combustion of methane is:
CH4 + 2O2 → CO2 + 2H2O
This equation tells us that 1 mole of methane reacts with 2 moles of oxygen to produce 1 mole of carbon dioxide and 2 moles of water.
- The types of atoms and molecules involved in the reaction: The chemical formulas in a balanced chemical equation indicate the types of atoms and molecules that are involved in the reaction. For example, the balanced chemical equation for the synthesis of ammonia is:
N2 + 3H2 → 2NH3
This equation tells us that the reaction involves nitrogen molecules (N2), hydrogen molecules (H2), and ammonia molecules (NH3).
- The physical states of the reactants and products: The subscripts in the chemical formulas in a balanced chemical equation indicate the physical states of the reactants and products. For example, the balanced chemical equation for the melting of ice is:
H2O(s) → H2O(l)
This equation tells us that the reaction involves solid water (H2O(s)) and liquid water (H2O(l)).
- Whether the reaction is exothermic or endothermic: The presence of a ΔH term in a balanced chemical equation indicates whether the reaction is exothermic (ΔH is negative) or endothermic (ΔH is positive). For example, the balanced chemical equation for the combustion of methane is:
CH4 + 2O2 → CO2 + 2H2O + ΔH
The presence of the ΔH term in this equation tells us that the combustion of methane is an exothermic reaction, meaning that it releases heat.
- The formation of precipitates: The presence of a solid product in a balanced chemical equation indicates that the reaction may form a precipitate. For example, the balanced chemical equation for the precipitation of lead chloride is:
Pb(NO3)2 + 2NaCl → PbCl2(s) + 2NaNO3
The presence of the solid product PbCl2(s) in this equation tells us that the reaction may form a precipitate of lead chloride.
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