ATOMS & ELEMENTS
What are all elements made of?
Atoms
What forms when two or more atoms bond together?
A molecule
What are the three common states of matter?
Solid, liquid, and gas
What happens to particles when they gain energy?
They move faster
What property tells how much mass is packed into a certain amount of space?
Density
What is an atom?
A very small particle that makes up matter
How many hydrogen atoms are in one molecule of H₂O?
2
In which state are particles packed tightly together?
Solid
What phase change happens when a solid becomes a liquid?
Melting
If two objects have the same volume, which one has greater density: the object with more mass or less mass?
The object with more mass
Why can't you see most atoms with your eyes?
They are extremely small
What two elements make up water?
Hydrogen and oxygen
In which state do particles move around most freely?
Gas
What phase change happens when a liquid becomes a gas?
Evaporation/vaporization
Which has greater density: 50 g in 10 mL or 100 g in 10 mL?
100 g in 10 mL
Which is an element: water, sugar, oxygen, or air?
Oxygen
Is O₂ an element or a compound?
Element
How do particles in a liquid move compared to particles in a solid?
Liquid particles can move past each other.
What happens to particles when matter changes from liquid to gas?
They gain energy, move faster, and spread farther apart.
Why can some objects float in water while others sink?
Objects less dense than water can float, while objects more dense than water sink.
What makes one element different from another element?
The type of atom it contains
What is the difference between an element and a compound?
An element contains one type of atom, while a compound contains two or more different types of atoms chemically bonded together.
How does particle spacing change when matter changes from a solid to a gas?
The particles become farther apart.
Why does dry ice change directly from a solid to a gas?
It does not form a liquid at atmospheric pressure; it changes directly from solid to gas.
An object has a mass of 200 g and a volume of 50 mL. What is its density?
4 g/mL