Chemical Reactions Quiz & Flashcards

Chemical reactions involve a change in chemical properties, unlike physical changes which only affect physical properties.

Increasing temperature generally increases reaction rates by providing more energy for molecular collisions.

The law of conservation of mass states that atoms are conserved in a chemical reaction.

Catalysts speed up reactions by lowering activation energy and are not consumed in the process.

The equilibrium constant expresses the ratio of concentrations of products to reactants at equilibrium.

Le Chatelier's Principle states that a system at equilibrium will adjust to minimize the effect of a disturbance.

In a double replacement reaction, two compounds exchange ions to form two new compounds.

Gibbs free energy indicates the spontaneity of a reaction; negative values suggest spontaneous reactions.

In reversible reactions, products can reform reactants, allowing for both forward and reverse reactions.

Oxidation involves the loss of electrons in a redox reaction.

Color of reactants does not affect the rate; temperature, concentration, and catalysts do.

A catalyst lowers the activation energy needed for a reaction, speeding up the process.

Higher concentration increases collision frequency among reactants, thus increasing the rate.

Combustion reactions typically produce water and carbon dioxide as products.

A decomposition reaction involves breaking down a compound into simpler substances.

Stoichiometric coefficients indicate the proportions of reactants and products involved in a reaction.

Exothermic reactions release energy, usually in the form of heat, to the surroundings.

A synthesis reaction involves the combination of elements or simpler compounds to form a complex compound.

Enzymes are biological catalysts that speed up reactions by lowering the activation energy required.

In a reversible reaction, products can convert back to reactants under certain conditions.

A reducing agent loses electrons and gets oxidized in a redox reaction.

Complete combustion of hydrocarbons produces carbon dioxide and water, not carbon monoxide.

A negative Gibbs free energy change indicates that a reaction can occur spontaneously.

In reduction, a species gains electrons, resulting in a decrease in oxidation number.

Chemical reactions result in the formation of new substances with different properties than the reactants.

Greater surface area allows more collisions between reactant particles, increasing the reaction rate.

Endothermic reactions absorb heat from the surroundings, resulting in a decrease in surrounding temperature.

Balancing ensures that the same number of each type of atom is present on both sides of the equation, in accordance with the conservation of mass.

A catalyst lowers the activation energy required for a reaction, allowing it to proceed more quickly.

In a single replacement reaction, an element in one compound is replaced by another element.

Increasing pressure compresses gases, leading to more frequent collisions and a higher reaction rate.

A heterogeneous catalyst is in a different phase than the reactants, typically providing a surface for the reaction.

In double replacement reactions, ions are exchanged between two compounds, forming new compounds.

Combustion reactions release energy, typically as heat and light, as substances react with oxygen.

Dynamic equilibrium is reached when the rates of forward and reverse reactions are equal, and concentrations stabilize.

A large equilibrium constant indicates that products are favored over reactants at equilibrium.

While catalysts speed up the attainment of equilibrium, they do not alter the equilibrium position.

Decomposition reactions involve breaking down a compound into simpler substances or elements.

Light provides the energy needed to start photochemical reactions, such as photosynthesis.

Catalysts are not consumed in the reaction; they facilitate the process and remain unchanged.

A spontaneous reaction occurs naturally without the need for continual external energy input.

Buffers resist changes in pH by neutralizing added acids or bases, maintaining the pH within a narrow range.

The formation of a new substance with different properties is a clear sign of a chemical reaction.

Melting ice is a physical change involving a change in state, not a chemical reaction.

A reaction mechanism provides a detailed sequence of steps that describe the pathway from reactants to products.

Increasing the surface area allows more particles to be exposed for reaction, thus increasing the rate.

Redox reactions involve the transfer of electrons between substances, encompassing both oxidation and reduction processes.

Increasing temperature increases the energy and frequency of collisions, but it does not affect activation energy.