Matter (elements, compounds, mixtures) Flashcards
(15 cards)
What is a pure substance?
Only made up of 1 type of atom
Each element has a different set of properties and can’t be separated into parts by any physical or chemical process.
Where are elements listed?
On the periodic table
Elements are represented by symbols.
What does each element have?
- Symbol
- Atomic number
- Atomic mass
These characteristics distinguish each element from others.
What is a compound?
A pure substance containing atoms of 2 or more elements, chemically bonded together, in a fixed ratio
Each compound has a unique set of properties.
Can compounds be separated into parts by physical processes?
No
Compounds can only be separated into their elements by chemical decomposition.
What is a mixture?
Not a pure substance with a variable composition and properties
Mixtures can be separated into parts by physical processes.
What are the two types of mixtures?
- Heterogeneous Mixture
- Homogeneous Mixture (a.k.a solution)
Each type has distinct characteristics.
What characterizes a heterogeneous mixture?
Do not have a uniform composition with visibly distinct components
Examples include a salad or fried rice.
What happens in a heterogeneous mixture like sand in water?
Sand particles settle at the bottom, forming a clear separation
This demonstrates the different properties of components.
What characterizes a homogeneous mixture?
Have a uniform composition with different components distributed evenly throughout
Examples include salty water and air.
Can mixtures appear uniform but be separated into components?
Yes
Unlike pure substances, mixtures can be separated into their separate components.
Why can’t molecular compounds be physically separated?
The bonds within the molecules are too strong to break physically
This prevents separation of different elements.
What happens in compounds that form lattices?
The chemical bonds are weaker and can be broken physically
Example: Crushing crystals of sodium chloride.
What does breaking a lattice only give you?
Smaller fragments of the lattice
You can never separate the different elements within the lattice.
What defines compounds as pure substances?
You can never physically divide them into different substances
This characteristic distinguishes compounds from mixtures.
