Density: The amount of matter that occupies a certain space. It is the mass per unit volume of a substance. Densities of Common Elements and Compounds Substance Density grams per mL or cc Water1.00 Aluminum, Al 2.70 Iron, Fe 7.80 Gold, Au Mercury, Hg 13.5

1. Lead is much more dense than iron. So given the same volume of each, lead will weigh more (have more mass). 2. Ice (solid) is less dense than water (liquid). Therefore ice floats on water Frozen Ice Liquid Water

Almost all chemical compounds are least dense in the gas form and increase in density towards the solid form. (Most dense) (Least dense) (Most dense) SolidLiquidGas (Least dense) Water Water densities: Gas = Least dense Liquid = Most dense Solid = Less dense than liquid (in water only!)

To calculate density you need two things: Mass and Volume D = density M = mass V = volume Can have several different units: kg/l g/ml g/cm 3 D = M V

A softball has a mass of 360 g and a volume of 270 cm 3. Find its density. Given: Mass = 360 g Volume = 270 cm 3 Required : Density (in g/cm 3 ) Answer : D = M/V = 360 g / 270 cm 3 = 1.33 g/cm 3

We measured the volume of a piece of copper by displacement in a beaker of water. The initial volume of water was 21ml and after placing our piece of copper into the beaker, the new volume was 26ml. Calculate the density this piece of copper weighing 53.47g. (remember density = mass / volume) Mass = 53.47g Volume = 26 ml-21 ml = 5 ml Density = g = g/ml 5 ml A pen has what density?

MassVolumeDensity 25 g40 mL 280 kg1.5 m 3 77 mg1.5 mL 2.0 mL1.5 g/mL 50 g25 g/L 250 mg1.0 mg mL 55 L4 kg/L 3.0 L g/ L 75 kg200L 50 g/L 290 g75 mL 50 g55 g/mL 200 L4.0 mg/L 1500 kg kg/m 3 48 g250 cm 3

MassVolumeDensity 25 g40 mL0.63 g/mL 280 kg1.5 m kg/m 3 77 mg1.5 mL51 mg/mL 3.0 g2.0 mL1.5 g/mL 50 g2.0 L25 g/L 250 mg250 mL1.0 mg mL 220 kg55 L4 kg/L g3.0 L g/ L 75 kg200L0.38 kg/L g200 L50 g/L 290 g75 mL3.9 g/mL 50 g0.91 mL55 g/mL 800 mg200 L4.0 mg/L 1500 kg m kg/m 3 48 g250 cm g/cm 3

Materials: 1 ziploc bag 1 teaspoon baking soda 1 teaspoon calcium chloride 30 mL phenol red solution Put a teaspoon of baking soda in one corner of the ziploc bag. Record your observations. Put a teaspoon of calcium chloride in the opposite corner of the ziploc bag. Record your observations.

Measure 30 mL of phenol red in a graduated cylinder. Pour half in the side with the baking soda. Feel the corner of the bag. Record all observations. WITHOUT MIXING, pour the other half of the phenol red in the side with the calcium chloride. Feel the corner of the bag. Record observations. Do this step over the sink. SEAL the ziploc bag well. Mix all the contents of the bag and observe what happens.

You are going to determine the density of 6 different objects. (4 provided, 2 you provide) Step 1: Find the mass of your object using the electronic scale (in grams and to 2 decimal places) Step 2: We will be using water displacement to calculate volume. Submerge the object in a graduated cylinder filled with water and note the volume change. final initial Volume of object = final volume after displacement – initial volume before displacement. Step 3: Calculate density.

ObjectMass (g)Volume (mL)Density (g/mL) 1. Bronze coloured cube 7.29 gVI = 19 mL VF = 20 mL VF-VI = = 1 mL D=M = 7.29g V 1 mL 7.29 g/mL

Matter: Matter: Anything that has mass and takes up space. Mixture: Mixture: Two or more substances mixed together. Pure Substance: Pure Substance: A substance that contains only one kind of matter. Mechanical Mixture: Mechanical Mixture: A mixture of two or more components that can be seen with the unaided eye.

Solutions: Solutions: A homogeneous mixture of two or more substances. Heterogeneous: Heterogeneous: Consisting of elements that aren’t all the same (variability). Homogeneous: Homogeneous: Uniform (the same) throughout. Precipitate: Precipitate: The formation of a solid in a solution during a chemical reaction.

Penny lab: You need to write a lab report following all the procedures outlined in the handout. Density questions: Last 3 pages: SHOW ALL WORK Example: Show formula used, show all units and show answer with correct units. WORK ON REVIEW! IF YOU WANT HELP  STUDY SESSION IN THE LAB ON WEDNESDAY AT LUNCH.