Question

name aaronaconeslac class 3rd chem date 9/18/25 chapter 3 states of matter section 3 changes of state before you read after you read this section, you should be able to answer these questions: • what is a change of state? • what happens during a change of state? • what can happen when a substance loses or gains energy? how are changes of state and energy related? it can be tricky to eat a frozen juice bar outside on a hot day. in just minutes, the juice bar begins to melt. as it melts, the juice bar changes its state from a solid to a liquid. a change of state happens when matter changes from one physical form to another. a change of state is always a physical change. remember that in a physical change, the substance does not change into a new substance. energy must be added or removed in order for a substance to change its physical state. it is important to remember that the particles of every substance move differently. this movement of particles depends on the state of the substance (solid, liquid, or gas). for example, the particles in frozen water or ice (a solid) only vibrate. the particles in liquid water move faster and have more energy than particles in ice. to change ice into liquid water, energy must be added. to change liquid water into ice, energy must be removed. the figure below shows changes of state that water can undergo. changes of state involving water are shown here. study tip compare as you read the chapter, complete a table with the following headings: • name of change • states that are changing • energy (added or removed). reading check 1. identify what must be added or removed when a substance changes state? take a look 2. describe what happens to water in a puddle before it forms droplets of liquid water in a cloud?

Explanation:

Step1: Identify key - concept from text

The text clearly states that energy must be added or removed for a substance to change state.

Step2: Answer Reading Check 1

Based on the above - mentioned concept, the answer to "What must be added or removed when a substance changes state?" is energy.

Step3: Analyze water cycle process for Reading Check 2

Water in a puddle evaporates. Evaporation is the process by which a liquid changes to a gas. The water molecules gain energy, move faster, and escape into the air as water vapor before forming droplets of liquid water in a cloud through condensation.

Answer:

1. Energy
2. The water in the puddle evaporates. The water molecules gain energy, move faster, and change from a liquid state to a gaseous state (water vapor) and rise into the air.