8th Grade Pure Substances and Mixtures PDF
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These notes cover the concepts of pure substances and mixtures in chemistry. They define pure substances, elements and compounds. There are also examples of mixtures, heterogeneous and homogeneous, and questions to identify which of the items shown are homogeneous or heterogeneous.
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Pure substance and mixtures A pure substance has only one type of molecules in it. A pure substance consists only of one element or one compound A mixture consists of two or more different substances, not chemically joined together A pure substance has only one type of molecule in it. Identify...
Pure substance and mixtures A pure substance has only one type of molecules in it. A pure substance consists only of one element or one compound A mixture consists of two or more different substances, not chemically joined together A pure substance has only one type of molecule in it. Identify which of these diagrams show a pure substance Elements Elements are the simplest pure substances. The smallest particle of an element that has the properties of that element is an atom. Examples: O-Oxygen H- Hydrogen Na- Sodium C- Carbon Fe- Iron Pb- Lead Compounds Compounds are pure substances that are made of more than one element bound together. A molecule is formed when two or more atoms chemically combine. Examples: H2O and CO2 Mixtures Homogeneous mixtures Components cannot be distinguished from each other, appear as one substance Particles distributed evenly throughout Example: air, 10 karat gold, salt water, Mixtures Heterogeneous mixtures • • All components of the mixture are visible because they do not mix together Particles are not distributed evenly Example: nut mix, vegetable soup, oil and water Identify these items as homogenous or heterogenous mixtures Identify these items as homogenous or heterogenous mixtures Identify these items as homogenous or heterogenous mixtures
