Question

the substances present before a chemical reaction are called: *
subscripts
reactants
catalyst
products
a solid that forms from a solution during a chemical reaction is a: *
solute
catalysts
solvent
precipitate
when balancing equations, why is it important to count each type of atom? *
to predict color changes
to make equations look simpler
to show the total mass has changed
to confirm the law of conservation of matter is followed

Explanation:

• For the first question: In a chemical reaction, reactants are the substances that undergo the reaction (present before the reaction). Subscripts are part of chemical formulas (e.g., in \(H_2O\), the '2' is a subscript). A catalyst speeds up a reaction but is not consumed (not the starting substances). Products are formed after the reaction.
• For the second question: A precipitate is a solid that forms from a solution during a chemical reaction. Solute is the dissolved substance in a solution. Solvent is the dissolving medium. Catalysts affect the reaction rate, not the formation of a solid from solution.
• For the third question: The Law of Conservation of Matter states that matter is neither created nor destroyed in a chemical reaction. By counting each type of atom (balancing the equation), we ensure that the number of atoms of each element is the same on both sides of the equation, thus confirming the law is followed. Predicting color changes is not related to atom - counting in balancing. Making equations look simpler is not the fundamental reason. The total mass does not change (due to the conservation law), so showing it has changed is incorrect.

Answer:

• First question: B. Reactants
• Second question: D. Precipitate
• Third question: D. To confirm the Law of Conservation of Matter is followed