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1 Density and states of matter Specification reference: P3.1.1 Density of materials Aims In this exercise, you will consider the term density and its relationship to the and volume of a variety of different materials. You will use the density equation to calculate the density of materials which exist in different states of matter and be able to explain how the density of a material is calculated. Learning objectives After completing this activity, you should be able to: apply the equation for density describe the apparatus used to find the density of a solid explain why different materials have different densities calculate density using the equation: density = volume Questions 1 Match the states of matter with their descriptions and the artwork showing the density of particles in that state. (3 marks) State of matter Statement Artwork Solid Particles are very far apart and move around quickly. Liquid Can flow or be poured. Gas Particles are closely packed together and vibrate about fixed positions. This resource sheet may have been changed from the original. 1

2 2 A block is found to have a of 840 g and a volume of 21 cm 3. What is its density? 3 The block below has a of 2400 g. Calculate its density. 4 Write an explanation, or simple method, describing how you would determine the density of an irregular solid, such as the one shown below. State all of the apparatus that would be needed, including any apparatus that is not shown here. (5 marks) This resource sheet may have been changed from the original. 2

3 5 The following table shows values for the densities of some solids and liquids. Use the data in the table to answer the questions that follow. In each case, state whether the statement is true or false and fully explain why. Solid Density in g/cm 3 Liquid Density in g/cm 3 concrete 2.60 water 1.00 lead alcohol 0.79 aluminium 2.71 mercury gold 19.3 sea water 1.03 lithium 0.53 olive oil 0.92 a A volume of 0.4 m 3 of gold will have the same as 0.4 m 3 of lead. (True/False) b Olive oil will float on water and on sea water but will sink in alcohol. (True/False) c 1 kg of gold will have seven times the volume of 1 kg of aluminium. (True/False) d A 1 m 3 volume of lead will have the same as 4.2 m 3 of aluminium. (True/False) This resource sheet may have been changed from the original. 3

4 6 Explain why different materials have different densities. Your answer should refer to how particles are arranged in the three different states of matter. This resource sheet may have been changed from the original. 4

5 Teacher bump up your grade Answers to questions 1 State of matter Statement Artwork (3 marks) Solid Particles are closely packed together and vibrate about fixed positions. Liquid Can flow or be poured. Gas Particles are very far apart and move around quickly. 2 density volume correct units of g/cm 3 (1) density (1), density volume correct units of g/cm 3 (1) (1), density 840 g (1), density 40 (1), 3 21cm g (1), final value of 2.4 (1), cm 4 Answer should include: measurement of volume from displacement can (1) where: water displaced volume of rock (1) measurement of (1) using an electronic balance (1) use of equation: density volume to calculate the density (1) 5 a False (1). Reference to, or calculation of, different densities leading to different es (1) b True (1). Density of olive oil is less than water and sea water but greater than that of alcohol (1) c False (1). Gold has a greater density than aluminium so equal es for both mean that gold will have a volume that is much less than that of aluminium (about 7 1 of that of aluminium) (1) (5 marks) d True (1). Use of = density volume for both leads to the same ; or a similar argument (1) This resource sheet may have been changed from the original. 2

6 Teacher bump up your grade 6 Answer should include: density (1) volume More atoms closely packed together means more than if fewer atoms are closely packed together (1). More atoms closely packed per unit volume means higher density compared with fewer particles packed together in a unit volume (1). Solids have more particles packed closely together per unit volume, so they tend to have a greater density than liquids or gases; or reverse argument (1). This resource sheet may have been changed from the original. 3