Bell Ringer Determine whether each of the following
Bell Ringer Ø Determine whether each of the following is an extensive or intensive property: l l volume density mass melting point
Matter and Change Classification of Matter
Pure Substances Ø every sample has same: l l characteristic properties composition Ø are made of: l one type of atom: element • Ex: iron, gold, oxygen l 2 or more types of atoms: compound • Ex: salt, sugar, water
Chemical Purity Ø chemicals in lab are treated as pure Ø all chemicals have some level of impurity Ø different grades of chemical are used for different purposes
Which are pure substances?
Mixtures Ø blend of 2 or more types of matter Ø each component keeps its own identity and properties Ø the components are only physically mixed Ø can be separated using physical means Ø properties of the mixture a combination of the properties of the componenent’s properties
Homogeneous Mixtures Ø Ø Ø also called solution uniform in composition no visible parts Ex: Ø vinegar Ø clear air Ø salt water Ø brass
Heterogeneous Mixtures not uniform in composition Ø visible parts Ø Ex: Ø soil Ø concrete Ø blood Ø chocolate chip cookies Ø sand in water Ø iced tea with ice
Mixtures
Physical Separation Techniques Filtration- solid part is trapped by filter paper and the liquid part runs through the paper Ø Vaporization- where the liquid portion is evaporated off to leave solid Ø
Physical Separation Techniques Decanting- when liquid is poured off after solid has settled to bottom Ø Centrifuge- machine that spins a sample very quickly so that components with different densities will separate Ø
Physical Separation Techniques Ø Paper Chromatography- used to separate mixtures because different parts move quicker on paper than other
Practice Determine whether each of the following is element, compound, homogeneous mixture or heterogeneous mixture. Ø Ø Ø Ø Ø air wood chlorine granite aluminum sugar in water blood sucrose stainless steel sodium chloride Ø Ø Ø Ø Ø brass whole milk apple table salt soft drinks vinegar concrete sodium baking soda (Na. HCO 3) gravel
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