are reactants consumed within a chemical reaction?
A reaction in which energy is absorbed from the surroundings is called an endothermic reaction. In endothermic reactions the enthalpy of the products is greater than the enthalpy of the reactants. Because reactions release or absorb energy, they affect the temperature of their surroundings. Exothermic reactions heat up their surroundings while endothermic reactions cool them down. The rate of a chemical reaction depends on the medium in which the reaction occurs. It may make a difference whether a medium is aqueous or organic; polar or nonpolar; or liquid, solid, or gaseous. Reactions involving liquids and especially solids depend on the available surface area. Pressure. Increasing the pressure of a reaction improves the likelihood reactants will interact with each other, thus increases the rate of the reaction. As you would expect, this factor is important for reactions involving gases, and not a significant factor with liquids and solids. STUDY OBJECTIVES. 1  Write mole ratios relating the amounts of reactants and products in a chemical reaction. 2  Calculate the mass of a substance that is produced or consumed in a chemical reaction, given the mass of any other species involved in the reaction. Step 1. Convert the amounts of given substances into moles if necessary. Step 2. Use the coefficients in the balanced equation to calculate the number of moles of the sought or unknown substance in the problem from the appropriate mole ratio. Step 3. Convert the number of moles of the needed substance into mass units if required. For solids, the shape and size of the reactants makes a big difference in the reaction rate. Presence of Catalysts and Competitors. Catalysts (e.g., enzymes) lower the activation energy of a chemical reaction and increase the rate of a chemical reaction without being consumed in the process. Exothermic and Endothermic Reactions [edit]. The release of energy in chemical reactions occurs when the reactants have higher chemical energy than the products. The chemical energy in a substance is a type of potential energy stored within the substance. This stored chemical potential energy is the heat content or enthalpy of the substance. In all stoichiometry problems the balanced chemical equation provides the bridge that allows us to relate the amount of a reactant to a given amount of another reactant, or to find the amounts required to yield a given amount of a product. Mole Ratios. Factors that influence the rate of a chemical reaction include temperature, state of matter of reactants, concentration, presence of catalysts, and pressure. PM Images, Getty Images. Anne Marie Helmenstine, Ph.D. 1 Use the chemical equation to find the number of moles of CaO that reacts per mole of SO 2. 2  From the balanced equation we can write: 1 mol CaO 1 mol SO 2. 3  Convert moles of CaO to grams of CaO using the molar mass of CaO.
Yes