Fundamental Concepts
What is the purpose of balancing a chemical equation?
To show that the number of atoms of each element is the same on both sides of the equation, reflecting conservation of matter.
What is combustion?
A reaction where a substance combines with oxygen to produce heat and light.
What indicates a chemical reaction?
Changes like color change or gas bubbles.
What happens to mass in a closed system?
It stays the same before and after the reaction.
Energy changes occur, but total mass stays the same.
Baking bread; the total mass remains the same.
What are reactants?
Substances that undergo a chemical change in a reaction.
In a decomposition reaction, what happens to the reactants?
They break down into simpler substances or elements.
How can we show conservation of matter in an experiment?
By measuring the mass before and after a reaction.
What is an endothermic reaction?
A reaction that takes in energy.
What is a misconception about conservation of matter?
That matter can be created or destroyed in a reaction.
How are products defined?
Substances formed as a result of a chemical reaction.
Name the reaction type that involves the exchange of ions between two compounds.
Double replacement reaction.
What shows that a gas is produced?
Bubbling or fizzing.
What is the role of energy in reactions?
Energy breaks bonds and forms new ones.
How is conservation of matter seen in recycling?
The mass stays the same, even when materials change.
Give an example of a physical change that does not involve conservation of matter.
A change of state, such as melting ice, where the amount of matter remains the same but changes form.
What type of reaction involves two or more substances combining to form one product?
Synthesis reaction.
Why is a closed container important?
It keeps matter from escaping.
How does combustion show conservation of mass?
The mass of reactants equals the mass of products.
Why do some think matter is lost in a reaction?
They see gases escape and think mass is gone.
What does conservation of matter mean in a chemical reaction?
The total mass of reactants equals the total mass of products; matter is neither created nor destroyed.
What type of reaction is A+B→AB?
Synthesis reaction.
Give an example of a reaction that shows conservation of matter.
Vinegar and baking soda produce gas but have the same total mass.
How do energy changes relate to conservation of matter?
Energy changes occur, but total mass stays the same.
How can teachers fix misconceptions about conservation of matter?
By doing experiments that show mass is conserved.