Matter
Anything that has mass and takes up space is called
Matter
Density describes how much _____ is packed into a certain amount of _____.
Mass; volume
Matter with a fixed, definite composition is called this. Only is one thing
A pure substance
Two or more substances physically combined but NOT chemically bonded form this.
A mixture
A pure substance consisting of only one type of atom is called this.
An element
Is Air matter?
Yes it takes up space
What is the formula for density?
Density = mass ÷ volume
D = m ÷ V
What are the two types of pure substances?
Elements and compounds
A mixture that is evenly mixed throughout is called this.
A homogeneous mixture
A pure substance made of two or more different elements chemically bonded together is called this.
A compound
what is an example of something that is not matter
light, heat, sound
Two objects have the same volume. Object A has a mass of 20 g and Object B has a mass of 50 g. Which is more dense?
Object B
True or False:
Elements are pure substances because they contain only one type of atom.
True
A mixture where you can see different parts or where the composition is not uniform is called this.
A heterogeneous mixture
Classify gold (Au) as an element, compound, or mixture.
Element
Name the two characteristics something must have to be considered matter.
It must have mass and take up space (volume).
Object A and Object B have the same mass, but Object A has a smaller volume. Which object has the greater density? Explain.
Object A — the same amount of mass is packed into a smaller volume.
Why is water (H₂O) considered a pure substance even though it contains hydrogen AND oxygen?
It is a compound with elements chemically bonded together in a fixed ratio.
Classify each as homogeneous or heterogeneous:
Salt water • Trail mix • Air • Cereal in milk
Salt water — homogeneous
Trail mix — heterogeneous
Air — homogeneous
Cereal in milk — heterogeneous
Classify carbon dioxide (CO₂) as an element, compound, or mixture AND explain your answer.
Compound — carbon and oxygen are chemically bonded in a fixed ratio.
A student says, “I can’t see the gas inside this balloon, so it isn’t matter.” Explain why the student is incorrect.
The gas has mass and takes up space, so it is matter even though it cannot be seen.
A block has a mass of 20 g and a volume of 10 cm³. What is its density?
2 g/cm³
Give me an example of a pure substance.
oxygen, gold, helium, carbon
A student mixes sand and water. Is the result a pure substance, homogeneous mixture, or heterogeneous mixture? Explain.
Heterogeneous mixture — the substances are physically combined and are not evenly distributed.
A student says, “Compounds can’t be pure substances because they contain more than one type of atom.” What is wrong with this statement?
Compounds are pure substances because their atoms are chemically bonded in a fixed ratio, giving them a definite composition.