Question:

# Density (g/cm Substance Identifying an Unknown Moterial by its Physical Properties Melting Point (c) 2.17 Mass (9) Color 801 Tab

Density (g/cm Substance Identifying an Unknown Moterial by its Physical Properties Melting Point (c) 2.17 Mass (9) Color 801 Table salt 14.5 white 1.53 148 Sugar 11.5 white 2.16 Baking soda 50 16.0 white 2.17 Unknown 801 white 16.0 LAB Manager Skill Practice: How can you calculate density? SC.8.P.8.3 Physical Lab: Identifying Unknown Minerals LAFS.68.WHST.1.2. LAFS.8.SL.1.1, SC.8.N.1.1, SC.8.N.1.5, SC.8.P.8.3, SC.8.P.8.4 Identifying Matter Using Physical Properties Physical properties are useful for describing types of matter, but they are also useful for identifying unknown substances. For example, look at the substances in the table above. Notice how their physical properties are alike and how they are different. How can you use these properties to identify the unknown substance? You cannot identify the unknown substance by its color. All of the substances are white. You also cannot identify the unknown substance by its mass or volume. Mass and volume are properties of matter that change with the amount of the sample present. m Photography/Digital NGSSS Check Metal Density (g/cm”) 2.70 Aluminum Zinc 713 Recall that melting point and density are properties of matter that do not depend on the size or the amount of the sample. Therefore, melting point and density are more reliable for identifying an unknown substance. Notice that both the melting point and the density of the unknown substance match those of table salt. The unknown substance must be table salt. Iron 7.87 Copper 8.96 6. Use the table above to determine the identity of a substance with a mass of 108 g and a volume of 40 cm. SC.8.P.8.3 When you identify matter using physical properties, consider how the properties are alike and how they are different from known types of matter. It is important that the physical properties you use to identify an unknown type of matter are properties that do not change for any sample size. A cup of salt and a spoonful of salt will have the same melting point and density even though the mass and volume for each will be different. Therefore, melting point and density are physical properties that are reliable when identifying an unknown substance. a