#1
Which of the following is a characteristic of a chemical reaction?
Change in color
Change in temperature
Formation of a precipitate
All of the above
#2
In a combustion reaction, what is typically one of the reactants?
Oxygen
Carbon dioxide
Water
Nitrogen
#3
What is the role of a catalyst in a chemical reaction?
Initiates the reaction
Slows down the reaction
Increases the activation energy
Speeds up the reaction without being consumed
#4
What is the role of enzymes in biological reactions?
Catalyze reactions
Inhibit reactions
Absorb heat
Initiate reactions
#5
What is the general form of a chemical equation?
Reactants → Products
Products → Reactants
Reactants + Products
Reactants = Products
#6
Which type of chemical reaction involves the exchange of ions between reactants?
Synthesis
Decomposition
Single displacement
Double displacement
#7
What is the main difference between exothermic and endothermic reactions?
Exothermic releases energy, endothermic absorbs energy
Exothermic absorbs energy, endothermic releases energy
Exothermic and endothermic have the same energy changes
None of the above
#8
What does the term 'stoichiometry' refer to in chemical reactions?
The study of reaction rates
The study of reaction mechanisms
The study of reactant and product quantities
The study of reaction equilibrium
#9
Which type of chemical reaction involves a substance combining with oxygen?
Synthesis
Decomposition
Combustion
Double displacement
#10
What is the product of the reaction between an acid and a base?
Water and salt
Carbon dioxide
Hydrogen gas
Oxygen gas
#11
Which of the following is an example of a redox reaction?
Combustion
Synthesis
Decomposition
Double displacement
#12
What is the law of conservation of mass in chemical reactions?
Mass is created in a reaction
Mass is destroyed in a reaction
Mass is conserved in a reaction
Mass is converted to energy in a reaction
#13
In a redox reaction, what is being oxidized?
Electrons gained
Protons gained
Electrons lost
Protons lost
#14
Which of the following is an example of a redox reaction in daily life?
Photosynthesis
Cellular respiration
Rusting of iron
Cooking pasta
#15
Which of the following statements about exothermic reactions is true?
They absorb heat from the surroundings
They release heat to the surroundings
They have a positive change in enthalpy
They always result in a decrease in temperature