Comparing the Physical Properties of Pure Substances 6.P.2.3.

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Comparing the Physical Properties of Pure Substances 6.P.2.3

Warm Up This is an example of matter; Can you identify it? How would you classify it? Think of ways scientists could classify different types of matter?

Classification of Gold At room temperature: Shiny Hard Does not dissolve in water Does not smell (no odor) Does not melt Density = 19.3 g/cm 3 Melting Point = 1062 °C Boiling Point = 2000 °C

What is Characteristic Properties? Characteristic properties of matter are used by scientists to identify/ classify different substances

Physical Properties: Properties that can be measured and observed (no chemical change to the substance) Includes: color, odor, density, solubility, melting point, boiling point

Vocabulary Classify- Physical Properties- are used to observe and describe matter without changing its property. synonyms: categorizecategorize, group, rank, rate, order, organize, range, sort, type,grouprankrate orderorganizerangesorttype assign (someone or something) to a particular class or category. "elements are usually classified as metals or nonmetals"

Ways to classify characteristic properties of matter State of Matter: – solid, liquid, gas Mass Volume Color Odor Density Visibility: – Translucent, transparent, opaque Solubility Melting Point Boiling Point Dull/ Shiny Texture Flexibility

DensityVolumeMassWeight How light or heavy something is because of its size. It determines an objects ability to sink or float. Density Mass = Density Volume How much space an object takes up Volume L x W x H= Volume or measure it with water with odd shaped objects It always stays the same. The amount of matter contained in an object. It is measured in grams and ounces. It always stays the same. The force of gravity on an object

Density Is a measurement of how tightly matter is crammed together. It tells you how light or heavy something is because of its size.

Measuring Volume Top Image: http://www.tea.state.tx.us/student.assessment/resources/online/2006/grade8/science/images/20graphicaa.gif Bottom Image: http://morrisonlabs.com/meniscus.htm We will be using graduated cylinders to find the volume of liquids and other objects. Read the measurement based on the bottom of the meniscus or curve. When using a real cylinder, make sure you are eye-level with the level of the water. What is the volume of water in the cylinder? _____mL What causes the meniscus? A concave meniscus occurs when the molecules of the liquid attract those of the container. The glass attracts the water on the sides.

Measuring Liquid Volume Images created at http://www.standards.dfes.gov.uk/primaryframework/downloads/SWF/measuring_cylinder.swf What is the volume of water in each cylinder? Pay attention to the scales for each cylinder.

Measuring Solid Volume Click here for an online activity about volumeClick here for an online activity about volume. Choose Lessons  Volume & Displacement 10 cm 9 cm 8 cm We can measure the volume of regular object using the formula length x width x height. _____ X _____ X _____ = _____ http://resources.edb.gov.hk/~s1sci/R_S1Science/sp/e n/syllabus/unit14/new/testingmain1.htm We can measure the volume of irregular object using water displacement. Amount of H 2 O with object = ______ About of H 2 O without object = ______ Difference = Volume = ______

Boiling Point

Boiling and Melting Points Boiling Point – The temperature at which liquid matter experiences the same pressure as the atmospheric pressure

Freezing and Melting Points 32 ͦF/ 0 ͦC Physical changes can involve changes in energy. Melting Point – The temperature at which solid matter turns to liquid Freezing Point – The temperature at which liquid matter turns to solid

Physical Changes States of matter change (solid, liquid, gas) due to changes in energy / temperature

Physical Changes Boiling and freezing are physical changes that make the molecules of a substance move faster or slower and be closer or farther apart. The molecules are not changed chemically!

Physical Properties Physical Properties involve things that can be measured without changing the chemical properties Some factors that can change the characteristic properties of matter are heat, temperature, and pressure

Physical Changes Matter can undergo physical changes that only affect physical properties Example : wood cut in half both pieces still have the same physical properties

Physical Properties of Matter Solubility – The ability for a substance to dissolve

Solutions, Solvents, & Solubility Solution- is a mixture of substances Solvent- is the part of the solution that is present in the greatest amount – The most common solvent is water. Solutes-is the part of the solution that gets dissolved in the solvent Solvent + Solutes = Solutions Water + Sugar = Sugar Water

SOLUBILITY Solubility = the amount of solute that will dissolve in a given amount of solvent at a given temperature An important factor that influences solubility is the temperature of the solute and the solvent. All things are not soluble

Factors Affecting Solubility The nature of the solute and solvent: different substances have different solubility Temperature: many solid substances become more soluble as the temp of a solvent increases; however, gases are less soluble in liquids at higher temps. Pressure: Only affects the solubility of gases. As pressure increases, the solubility of gases increases.

Soluble or Insoluble? Activity Observations SolutionsIt looks as though none of the substance has disappeared It looks as if all or most of the substance has disappeared sugar salt sand oil Vinegar copper sulfate