Chemical Reactions Quiz

What occurs when chemical bonds between atoms are formed or broken?

• A) A physical change

• B) A phase transition

• C) A chemical reaction

• D) A nuclear reaction

What are the substances that go into a chemical reaction called?

• A) Products

• B) Catalysts

• C) Reactants

• D) Enzymes

What are the substances produced at the end of a chemical reaction known as?

• A) Reactants

• B) Catalysts

• C) Enzymes

• D) Products

What is the correct representation of the decomposition of hydrogen peroxide (H2O2)?

• A) H2O2 → H2 + O2

• B) H2 + O2 → H2O2

• C) 2H2 + O2 → 2H2O + O2

• D) 2H2O2 → 2H2O + O2

What are the numbers in front of the chemical formulas in a chemical equation called?

• Subscripts

• Products

• Coefficients

• Reactants

What is the purpose of coefficients in a chemical equation?

• To indicate the physical states of the compounds

• To balance the equation by ensuring the same number of atoms of each element on both sides

• To show the temperature at which the reaction occurs

• To name the compounds involved in the reaction

What does it mean for a chemical equation to be balanced?

• The equation has an equal number of molecules on both sides

• The equation has an equal number of atoms of each element on both sides

• The equation only contains gases and liquids

• The equation represents a reversible reaction

Why must equations be balanced according to the image?

• To follow the law of conservation of energy

• To reflect the law of conservation of matter

• To comply with the law of multiple proportions

• To ensure the reaction happens faster

What do coefficients in chemical equations represent according to the image?

• The number of molecules in a compound

• The relative proportions of elements in a compound

• The charge of the ions in a compound

• The balance of chemical equations

What does a subscript in a chemical formula indicate as per the image?

• The charge of the ion

• The number of atoms of that element

• The number of molecules

• The coefficient of the element