Chemical Reactions
A student mixes vinegar and baking soda in a container. The container begins to bubble, and a gas is produced. What evidence shows that a chemical reaction occurred?
Gas production (bubbling), formation of a new substance, and possible temperature change.
Matter with a definite shape and volume.
Solid
System that controls and responds to stimuli.
Nervous System
When iron reacts with oxygen, rust forms. The new substance has different properties than the original materials. What type of change is this, and what evidence supports it?
A chemical change, because a new substance with different properties is formed.
A solid forms when two liquids are combined.
Precipitate
Structures that detect changes in the environment.
Sensory Receptors
What is the Law of Conservation of Mass?
Matter cannot be created or destroyed in a reaction.
The system that allows oxygen to enter the body.
Respiratory System
Why does mass appear not to be conserved in an open system?
Gas escapes during a reaction, making it seem like mass is lost.
Explain how body systems work together during exercise.
(respiratory + circulatory) to deliver oxygen and energy
A student claims dissolving salt in water is a chemical change.
Why is this incorrect?
Because no new substance is formed.