Pure Substance - Socorro Independent School District

Bell Ringer Aug. 23 If gases are compressible, why does a balloon filled with helium pop when you squeeze it in you hands? Classifying Matter by Composition Another way to classify matter is to examine its composition.

composition includes: types of particles arrangement of the particles attractions and attachments between the particles 2 3 Group Notes

You have 20 minutes All group members must have the notes in their notebooks. Use the Wi-Fi. Pure Substance Matter whose composition does not change from one sample to another is called a pure substance. made of a single type of atom or molecule Because the composition of a pure substance is always the same, all samples have the same characteristics.

Examples: Elements Compounds Mixture blend of 2 or more types of matter

each component keeps its own identity and properties the components are only physically mixed can be separated using physical means properties of the mixture are a combination of the components properties Examples: Heterogeneous Mixtures Homogeneous Mixtures Element Pure substances that cannot be

decomposed into simpler substances by chemical reactions are called elements. These are found on the periodic table of elements decomposed = broken down basic building blocks of matter composed of single type of atom though those atoms may or may not be combined into molecules Compound Substances that can be decomposed are called compounds.

chemical combinations of elements composed of molecules that contain two or more different kinds of atoms All molecules of a compound are identical, so all samples of a compound behave the same way. Most natural pure substances are compounds. Homogenous Mixture

homogeneous = mixture that has uniform composition throughout Every piece of a sample has identical characteristics, though another sample with the same components may have different characteristics. atoms or molecules mixed uniformly Heterogeneous Mixture heterogeneous = mixture that does not have uniform composition throughout contains regions within the sample with

different characteristics atoms or molecules not mixed uniformly Determine whether each of the following is element, compound, homogeneous mixture or heterogeneous mixture .

air zinc chlorine granite aluminum sugar in water blood Sucrose (C12H22O11) stainless steel sodium chloride (NaCl)

brass whole milk apple table salt (NaCl) soft drinks vinegar concrete sodium

baking soda (NaHCO3) gravel Closing Task Aug. 23 Write a 4 sentence summary about the differences between mixtures and pure substances.