How can matter be classified Atoms are the smallest unit of an element that maintains the properties of that element The most basic ingredients to all matter Atoms can be combined in three majors ways ID: 649705
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Slide1
Pure Substances and MixturesSlide2
How can matter be classified?
Atoms
are the smallest unit of an element that maintains the properties of that element.
The most basic ingredients to all matterAtoms can be combined in three majors ways:To make elementsTo make compoundsTo make mixturesSlide3
Legos!
We can use
legos
to help us figure out the differences between atoms, elements, compounds, and mixturesElements are made up of one or more of the same kind of atom chemically combinedCompounds are made up of different kinds of atoms chemically combined. They have different properties than the atoms that make them upA mixture contains a variety of elements and compounds that are physically combined.Slide4
Pure Substances
Elements and compounds make up pure substances
A pure substance has definite physical and chemical properties
No matter how much of a pure substance you have, it will always have the same propertiesSlide5
Pure Substances
Pure substances are made up of one type of particle
One type of element or one type of compound
Each compound is a chemically combined particle or moleculeEx. Every water molecule is exactly the sameSlide6
Pure Substances
Pure substances cannot be formed or broken down by physical change
Chemical bonds that are holding the atoms together require a lot of energy to break. In order to do this we need a chemical change.
If we were to break apart water we would end up with 2 hydrogen atoms and an oxygen atomSlide7
Classifying Elements
Based on their chemical and physical properties we can categorize elements
Some of these categories include metals, nonmetals, or metalloids
Over 100 elements are known to existThey are found on the periodic tableThe periodic table separates the metals, nonmetals, and metalloids by the staircaseSlide8
Classifying Compounds
By pH
Acidic if pH is lower than 7 (sharp sour taste)
Basic if pH is higher than 7 (slippery feel, bitter)Neutral if pH is 7 (form when acids and bases react) examples pure water and saltWe test pH using litmus paper that changes color depending on the pHDO NOT TASTE OR TOUCH IN LABSlide9
Classifying Compounds
As Organic or Inorganic
Organic has carbon and hydrogen atoms
Organic would be in foods and other types of living thingsBy their role in the bodyBiochemicalsCarbohydratesLipidsProteinsNucleic acidsSlide10
Mixtures
A mixture is a combination of two or more substances combined physically
Mixtures are made up of more than one type of particle
The properties of these particles remain unchangedMixtures do not have their own defined propertiesMixtures can be separated by physical changesSlide11
Ways to separate mixtures
By hand
Centrifuge (density)
MagnetsBoiling off solutionsSlide12
Classifying Mixtures
A
heterogeneous
mixture is one that does not have inform compositionA homogeneous mixture is one that is evenly spread throughoutWhen something totally dissolves it forms a homogeneous mixtureSlide13
Other Ways to Classify Mixtures
Suspension
- mixtures in which the particles of a material are spread throughout a liquid or gas but are too large to stay mixed without being shaken or stirred
HeterogeneousSlide14
Other Ways to Classify Mixtures
Solutions
- one substance is dissolved in another substance
HomogeneousSlide15
Other Ways to Classify Mixtures
Colloids
- between a suspension and solution
Particles are spread throughout but do not settle quicklyMilk and gelatin are good examples Heterogeneous despite looking homogeneous