Using the formula for density, answer the following calculation problems. M D = (g/ml or g/cm 3 ) Density = Mass D = M M = (g) Volume V D V V = (ml or cm 3 ) For all of your problems, please complete them with the following methods to obtain full marks: 1 mark for LISTING your variables (including units and the unknown) 1 mark for choosing the right FORMULA (write out the entire formula) 1 mark for the WORK shown (including units) 1 mark for the correct ANSWER (including the units) **Sometimes, the object s volume is noted in ml. Please be aware that in most cases: 1 cm 3 (ice) = 1 ml (pure water) Solids, Gases are measured in cm 3, Liquids in ml Part A: Calculations (Eg 1) Calculate the density of an object having a mass of 10 g and a volume of 2 cm 3. D =? D = M = 10 g = 5 g/cm 3 M = 10 g V 2 cm 3 V = 2 cm 3 5 g/cm 3 (Eg 2) Calculate the density of a 120 g object with a volume of 60 ml. D =? D = M = 120 g = 2 g/ml M = 120 g V 60 ml V = 60 ml 2 g/ml (Eg 3) If an object has a density of 0.35 g/cm 3, what is the mass if it s volume is 350 cm 3? D = 0.35 g/cm 3 M = D V M =? = (0.35 g/cm 3 )(350 cm 3 ) V = 350 cm 3 = 122.5 g 122.5 g (Eg 4) Given a density of 2.25 g/cm 3, what is the volume if an object s mass is 675 g? D = 2.25 g/cm 3 V = M = 675 g = 300 cm 3 M = 675 g D 2.25 g/cm 3 V =? 300 cm 3
1. A sample of quartz was found to have a mass of 130 g and to occupy a volume of 50 cm 3. What is the density of quartz? (1 decimal) D =? D = M = 130 g = 2.6 g/cm 3 M = 130 g V 50 cm 3 V = 50 cm 3 2.6 g/cm 3 2. A substance has a mass of 42 g and occupies 294 cm 3. What is its density? (2 decimals) D =? D = M = 42 g = 0.14 g/cm 3 M = 42 g V 294 cm 3 V = 294 cm 3 0.14 g/cm 3 3. If the volume of an object is 100 cm 3 and its density is 1.20 g/cm 3, what is its mass? D = 1.20 g/cm 3 M = D V M =? = (1.20 g/cm 3 )(100 cm 3 ) V = 100 cm 3 = 120 g 120 g 4. The average human body has 6820 ml of blood that has a mass of 7229.2 g. What is the density of human blood? (2 decimals) D =? D = M = 7229.2 g = 1.06 g/ml M = 7 229.2 g V 6820 ml V = 6 820 ml 1.06 g/ml 5. Find the volume of piece of brass (density 8.4 g/cm 3 ) and a mass of 600 g. (1 decimal) D = 8.4 g/cm 3 V = M = 600 g = 71.4 cm 3 M = 600 g D 8.4 g/cm 3 V =? 71.4 cm 3 6. Calculate the density of a solid block that has a volume of 600 cm 3 and a mass of 150 g. D =? D = M = 150 g = 0.25 g/ cm 3 M = 150 g V 600 cm 3 V = 600 cm 3 0.25 g/cm 3 7. Calculate the volume of carbon dioxide gas (density = 0.002 g/cm 3 ) and a mass of 500 g. D = 0.002 g/cm 3 V = M = 500 g = 250 000 cm 3 M = 500 g D 0.002 g/cm 3 V =? 250 000 cm 3
Part B: Use the Density Chart on the back to complete the following questions. 11. If the following liquids were mixed in a cylinder and allowed to settle out, state the order of liquids from bottom to top. Rank starting from 1 as being the bottom. Assume they will NOT dissolve in each other. a) _2 anti-freeze, _1 glycerin, _3 turpentine b) _1 mercury, _4 gasoline, _2 sea water, _3 ethyl alcohol c) _3 sea water, _4 oil, _5 kerosene, _1 molasses, _2 saturated salt water d) _5 ethyl alcohol, _4 kerosene, _1 molasses, _3 water (4 C), _2 anti-freeze 12. List all the solids (from the chart on the back page) that would sink in mercury (13.5). Gold (19.3) Osmium (22.7) Platinum (21.5) 13. Why does a marshmallow float on top of hot chocolate? Marshmallows are less dense (lots of air) than water 14. Why does a melted marshmallow sink to the bottom of hot chocolate? Melted marshmallows have no air and is more dense than water 15. Why must you always shake a mix of oil and vinegar dressing before serving it? Oil and vinegar don t mix due their different densities (and strong attraction for their own type of particles). After sitting, the two substances separate and so it needs to be shaken first. 16. Why does a hot air balloon rise? (Hint: List the densities of air and helium) How air balloons are filled with helium (which is less denser than air). When filled, the balloon becomes less dense than air and rises. 17. Why do bubbles rise to the top of a bottle of pop (Hint: List the densities of water and carbon dioxide) Carbon dioxide gas is less dense than the water (solvent) in the pop. (0.002 g/cm 3 ) (1.0 g/ml)
SOLIDS 20 0 C g/cm 3 Density Information LIQUIDS g/ml Aluminum 2.7 Amber 1.1 Ash wood 0.6 0.8 Balsa wood 0.34 Beech wood 0.7 0.9 Birch wood 0.55 0.71 Brass 8.44 Butter 0.86 Cast iron 7.0 Cedar 0.5 0.6 Chalk 2.0 Cork 0.25 Bone 1.8 Copper 8.9 Diamond 3.5 Eggs 1.02 Glass 2.4 Gold 19.3 Granite 2.5 3.0 Graphite 2.2 Ice (0 0 C) 0.92 Iron 7.9 Lead 11.4 Magnesium 1.7 Manganese 7.2 Nickel 8.9 Oak 0.7 0.9 Osmium 22.7 Pine 0.4 0.5 Plastic 1.01 1.4 Platinum 21.5 Quartz 2.65 Rubber 1.2 Salt 2.18 Silicon 2.3 Silver 10.5 Sodium 0.97 Spruce 0.48 0.7 Steel 7.8 Styrofoam 0.005 Tin 7.3 Uranium 19.1 Vinyl 1.38 1.4 Zinc 7.1 Anti-freeze 1.1 Ethyl alcohol 0.79 Gasoline 0.70 Glycerin 1.26 Kerosene 0.82 Mercury 13.5 Methyl alcohol 0.79 Molasses 1.4 Oil 0.9 Saturated salt water 1.1 Sea water 1.025 Turpentine 0.87 Water (4 0 C) 1.0 GASES (0 0 C / sea level) g/cm 3 Air 0.0013 Carbon dioxide 0.002 Helium 0.0002 Hydrogen 0.00009 Neon 0.009 Nitrogen 0.0013 Oxygen 0.0014