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Density Name: Kenneth Tan Jun Wei Class: 102 Index Number: 16 ACE: Term 2 1 What is Density? • • • Known as mass per volume Used to measure a material or objects compactness A form of describing mass in a continuous system 2 Factors that affect Density • • • • Mass of an object Volume of an object What kind of state is the object in e.g. solid state, liquid state, gaseous state etc Regular or irregular shaped 3 Units of Density • • 3 3 SI unit for Density is kg/m or g/cm One thousand kilograms per cubic meter equals one gram per cubic centimeter 3 3 [1000 kg/m = 1 g/cm ] 4 Formula to finding Density Formula: Mass Density= Volume E.g. The mass of iron is 27kg and its volume 3 is 3m , find the density of iron. Density= 27kg 3m 3 =9kg/m 3 5 Steps taken to find Density of an object Step 1: Measure the mass and volume of the substance Step 2: Divide the mass of the substance by its volume Density= Mass Volume 6 Steps taken to find density of a regularly shaped object Step 1: Measure the mass and calculate from dimensions, the volume of the object Mass Step 2: Density= Volume 7 Steps taken to find density of an irregularly shaped object First place the egg on a measuring scale and you will be able to find the egg’s mass. 8 Next, fill the eureka beaker until water starts flowing out of its spout. Allow it to stand until it stops to flow. 9 Then, place a measuring cylinder right below the spout and slowly lower the egg into the water. volume of the egg=volume of the water that flows out of the spout Density= Mass Volume 10 Steps taken to find density of a liquid The steps that have to be taken to find density of water is similar to the steps taken to find a substance. Step 1: Measure the mass and volume of the liquid Step 2: Divide the mass and the volume of the liquid Mass Density= Volume 11 Steps taken to find Density of Gas Step 1:Take the molecular formula weight of the gas (grams per mole—from the periodic table) Step 2:Divide that by the standard molar volume for a gas, which is 22.4 L per mole FW density= 22.4 12 Solids and their Density Substance Platinum Gold Lead Silver Copper Iron Zinc Aluminium Ice g/cm 3 21.5 19.3 11.3 10.5 8.5 7.9 7.1 2.7 0.92 13 Solids and their Density Substance Glass Pinewood cork g/cm 3 2.5 0.50 0.24 14 Liquids and their Density Substance g/cm 3 Mercury 13.26 Glycerine 1.26 Sea Water 1.03 Pure Water( at 4 degrees 1.00 Celsius) Olive Oil 0.92 Turpentine 0.87 Petrol 0.80 Alcohol 0.79 15 Gases and their Density Substance Air Hydrogen Helium Nitrogen Oxygen Carbon Dioxide g/cm 3 0.00129 0.00009 0.0001663 0.001251 0.0013 0.00195 16 Floating and Sinking Some objects float while others sink. • • The deciding factor whether the object floats or sinks is actually density. Objects that float on water have a lower density than water, while objects that sink have a higher density than water. 17 Picture of objects that float and sink in water. Objects that float have a smaller density than water. While, objects that sink have a higher density than water. 18 Sources • • • • http://www.engineeringtoolbox.com/density -specific-weight-gravity-d_290.html karentimberlake.com/ppz/density.ppt http://www.sparknotes.com/testprep/books/ sat2/chemistry/chapter5section11.rhtml http://morrisonlabs.com/density_chart.htm 19 Density Thank you for your kind attention 20