Conservation of Mass
What does the Law of Conservation of Mass state?
Mass cannot be created or destroyed in a chemical reaction.
What do the numbers in front of chemical formulas represent in an equation?
Coefficients, which show the number of molecules or moles.
What type of reaction combines two or more substances to form one product?
Synthesis reaction.
What are the starting substances in a chemical reaction called?
Reactants
Why do engineers need to understand the Law of Conservation of Mass?
To design safe chemical processes and ensure materials are accounted for in reactions.
True or False: The mass of the reactants is always equal to the mass of the products.
True
Balance this equation: H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O.
In a combustion reaction, what two main products are usually formed?
Carbon dioxide (CO₂) and water (H₂O).
What are the substances formed after a chemical reaction called?
Products
What happens to the mass of a log when it burns completely?
The mass converts to ash, gases, and energy, but the total mass remains constant.
If you start with 50 grams of reactants, how much should the products weigh?
50 grams
What does the arrow (→) mean in a chemical equation?
It shows the direction of the reaction, meaning "yields" or "produces."
Identify the reaction type: AB → A + B
Decomposition reaction
What is the small number written to the right of an element in a chemical formula?
Subscript, indicating the number of atoms of that element.
In a closed system, why is it important to prevent leaks during a chemical reaction?
To ensure the mass of products matches the mass of reactants, following the Law of Conservation of Mass.
Why does the total mass of a reaction stay constant?
Atoms are rearranged but not created or destroyed.
What must be true for a chemical equation to be balanced?
The number of each type of atom must be equal on both sides.
What happens to atoms during a chemical reaction?
They are rearranged into new substances.
What is a catalyst?
A substance that speeds up a reaction without being consumed.
Name a real-world process where balancing chemical equations is essential.
In industrial chemical manufacturing, like producing fertilizers or medicines.
During a chemical reaction in a closed system, why doesn’t the mass change?
No matter or gas escapes, and all atoms are accounted for.
Why do we balance chemical equations?
To follow the Law of Conservation of Mass.
Give an example of an exothermic reaction
Combustion or a reaction that releases heat.
Define "precipitate" in a chemical reaction
A solid formed when two solutions react.
How is the Law of Conservation of Mass applied in environmental science?
It helps scientists track pollutants and understand how matter cycles in ecosystems.