ATOMS & MOLECULES
This is the smallest unit of matter that keeps the properties of an element.
Atom
Cutting paper is an example of this type of change.
Physical change
What happens to particle motion when thermal energy increases?
Particle motion increases
During a chemical reaction, atoms are:
conserved
This natural resource is used to make many synthetic materials.
Oil (petroleum)
This is made when two or more atoms are chemically bonded together.
Molecule
This type of change forms a new substance.
Chemical change
When thermal energy is removed, matter usually changes toward this state.
Solid
What happens to atoms during a chemical reaction?
rearranged
Plastic is an example of this type of material.
Synthetic materials
Water (H₂O) is an example of this type of particle.
Molecule
Which property helps prove a chemical reaction happened: shape or gas?
Gas
Why does a balloon expand in hot water?
Particles move faster and collide more
True or False: Atoms disappear during reactions.
False
One benefit of synthetic materials is that they are often __________.
Useful / strong / lightweight / cheap (any valid)
Why is NaCl NOT considered a molecule?
It forms a repeating pattern (extended structure)
Why does a change in shape NOT prove a chemical reaction?
Shape is a physical property
Put these in order:
Thermal Energy → ______ → State Change
Particle motion
Why does mass sometimes appear to decrease when gas is produced?
One environmental consequence of synthetic materials is __________.
Pollution / waste / microplastics
What is the difference between a simple molecule and an extended structure?
Molecules are small groups; extended structures repeat endlessly
What evidence BEST shows a chemical reaction occurred?
A new substance formed (gas, color change, heat, etc.)
Explain why pressure increases when a gas is heated in a closed container.
Faster particles collide more often with the walls
What must you check if mass looks different before and after a reaction?
If the system is open or closed
Why must synthetic materials be used responsibly?
They help society but can harm the environment