Balancing Equations And Chemical Reactions: Quiz

A reaction that causes a chemical change is called a chemical reaction. This is because a chemical reaction involves the breaking and forming of chemical bonds, resulting in the formation of new substances with different properties from the original substances. In contrast, a physical change refers to a change in the physical state or appearance of a substance, without any alteration in its chemical composition. A flare and light are not specific terms for reactions causing chemical changes, but rather refer to the emission of light or a specific device used to produce light.

Exothermic reactions release heat energy. This means that during these reactions, energy is being released in the form of heat. This is in contrast to endothermic reactions, where heat energy is absorbed. Exothermic reactions can occur in various substances and are not limited to humans.

Reactants and products are both parts of chemical equations. In a chemical equation, reactants are the substances that undergo a chemical change, while products are the substances that are formed as a result of the chemical reaction. Chemical equations are used to represent the reactants and products involved in a chemical reaction, and they provide a balanced representation of the conservation of mass.

Endothermic reactions refer to chemical reactions that absorb heat energy from their surroundings. These reactions require an input of energy to proceed and result in a decrease in temperature of the surroundings. This is because the reactants in an endothermic reaction have lower energy than the products, and the additional energy is absorbed from the surroundings. Therefore, the correct answer is "absorb heat energy."

Subscripts in a chemical equation indicate the number of atoms present in the equation. They are used to balance the equation and show the stoichiometry of the reaction. By using subscripts, we can determine the exact number of each type of atom involved in a chemical reaction.

In chemical equations, coefficients represent the number of molecules or atoms involved in a reaction, while subscripts indicate the number of atoms of a particular element in a molecule. Therefore, the correct answer is "coefficients and subscripts".

The energy released in reactions can be released in the form of sound, heat, and light. However, it is not released in the form of food. Food is a source of energy, but it is not a way in which energy is released during reactions.

Coefficients tell us how many molecules are in the equation. In a chemical equation, coefficients are used to balance the number of molecules on each side of the equation. They represent the ratio of molecules participating in the reaction. By adjusting the coefficients, we can ensure that the number of molecules of each element is the same on both sides of the equation, thus maintaining the law of conservation of mass. Therefore, coefficients provide crucial information about the quantity of molecules involved in a chemical equation.

If energy is written on the reactants side of an equation, it likely means that activation energy is required to start the reaction. Activation energy is the minimum amount of energy needed for a chemical reaction to occur. By including energy as a reactant, it indicates that the reaction requires an input of energy to initiate the reaction and overcome the energy barrier. This energy can come in the form of heat, light, or any other form of energy.

The color of a substance does not have a direct impact on the rate of a chemical reaction. The rate of a chemical reaction is typically influenced by factors such as concentration, temperature, and surface area. Concentration refers to the amount of reactants present, temperature affects the kinetic energy and collision frequency of particles, and surface area affects the contact between reactant molecules. However, color is not directly related to these factors and therefore does not affect the rate of a chemical reaction.