Mixture
What is a mixture?
A mixture is a combination of two or more substances that are not chemically joined together.
Element
What is a pure substance?
A pure substance is made of only one kind of particle.
What is a compound?
A compound is a pure substance made when two or more elements combine chemically
What is the difference between a homogeneous mixture and a heterogeneous mixture?
A homogeneous mixture has the same composition throughout (uniform), while a heterogeneous mixture has visibly different parts.
Water
Compound
What are the two types of pure substances?
Elements and compounds
How are the elements in a compound joined together?
They are joined by chemical bonds.
Give two examples of homogeneous mixtures and two of heterogeneous mixtures.
Homogeneous: salt water, air.
Heterogeneous: salad, sand and water.
Sand
mixture.
Why can’t pure substances be separated by physical methods?
Because their particles are chemically bonded or identical.
Can a compound be separated by physical methods?
No, only by chemical changes.
How can mixtures be separated into their components?
They can be separated by physical methods such as filtration, evaporation, or using a magnet.
Oxygen
element.
Give two examples of pure substances.
Gold and oxygen.
Give two examples of compounds.
Give two examples of compounds.
Is salad a mixture? Explain why or why not.
Yes, salad is a mixture because it contains different ingredients that are not chemically combined and can be easily separated.
Rock
mixture
Do pure substances have the same composition everywhere?
Yes, they are uniform throughout.
Do compounds have the same properties as their elements?
No, they have completely new properties.