#1
Which of the following is a characteristic of a chemical reaction?
All of the above
ExplanationChemical reactions involve changes in energy, formation of new substances, and rearrangement of atoms.
#2
In a combustion reaction, what is typically one of the reactants?
Oxygen
ExplanationCombustion reactions require oxygen as a reactant to support the combustion process.
#3
What is the role of a catalyst in a chemical reaction?
Speeds up the reaction without being consumed
ExplanationCatalysts increase the rate of a chemical reaction by providing an alternative reaction pathway, without being consumed in the process.
#4
What is the role of enzymes in biological reactions?
Catalyze reactions
ExplanationEnzymes act as biological catalysts, speeding up chemical reactions in living organisms.
#5
What is the general form of a chemical equation?
Reactants → Products
ExplanationChemical equations represent the transformation of reactants into products, typically written in the form of reactants arrow products.
#6
Which type of chemical reaction involves the exchange of ions between reactants?
Double displacement
ExplanationIn double displacement reactions, ions from two compounds exchange places, forming new compounds.
#7
What is the main difference between exothermic and endothermic reactions?
Exothermic releases energy, endothermic absorbs energy
ExplanationExothermic reactions release energy to the surroundings, while endothermic reactions absorb energy from the surroundings.
#8
What does the term 'stoichiometry' refer to in chemical reactions?
The study of reactant and product quantities
ExplanationStoichiometry is the study of the quantitative relationships between reactants and products in chemical reactions.
#9
Which type of chemical reaction involves a substance combining with oxygen?
Combustion
ExplanationCombustion reactions involve the rapid combination of a substance with oxygen, often producing heat and light.
#10
What is the product of the reaction between an acid and a base?
Water and salt
ExplanationThe reaction between an acid and a base results in the formation of water and a salt.
#11
Which of the following is an example of a redox reaction?
Combustion
ExplanationRedox reactions involve the transfer of electrons, as seen in combustion reactions.
#12
What is the law of conservation of mass in chemical reactions?
Mass is conserved in a reaction
ExplanationThe total mass of reactants is equal to the total mass of products in a chemical reaction, following the law of conservation of mass.
#13
In a redox reaction, what is being oxidized?
Electrons lost
ExplanationOxidation involves the loss of electrons, so the substance being oxidized loses electrons.
#14
Which of the following is an example of a redox reaction in daily life?
Rusting of iron
ExplanationThe rusting of iron involves the oxidation of iron, making it an example of a redox reaction.
#15
Which of the following statements about exothermic reactions is true?
They release heat to the surroundings
ExplanationExothermic reactions release heat energy to the surroundings.