Presentation on theme: "Density a physical property of matter Property = a characteristic that gives a substance identity Properties of Vinegar: - clear liquid - strong odor."— Presentation transcript:
Property = a characteristic that gives a substance identity Properties of Vinegar: - clear liquid - strong odor - reacts with baking soda - acidic
Physical Properties can be observed without changing the composition of the substance Examples; -Color -Texture -Shape -Hardness -Buoyancy -Viscosity -Miscibility -Density
DENSITY StyrofoamBrick Brick is more dense than Styrofoam because there is more mass packed into the same volume (more molecules or atoms in the same space.)
Density Density can be defined as unit mass per unit volume Density = Mass / Volume D = m / v
Example: Density Density is a property of matter. If you measure the mass and the volume of an object, you can calculate its density using the formula: (g) (mL) D = m/v Density = mass/volume So, the units of density must be…. g/mL
The Units for density come from this formula… Why is density measured in g/mL? Because the formula for density is (akagrams per milliliter) (notgee slash em-ell) m mass (in grams) g D = ----- = ------------ -------------- ---- v volume (in milliliters) mL
Metric System ssecondTime K or o C Kelvin or degree celsius Temperature LliterVolume ggramMass mmeterLength Unit Symbol UnitQuantity
Volume is special because: Volume can be measured in liters (L), milliliters (mL), etc. s or…
OR… Volume can be measured in cubic meters (m 3 ) centimeters (cm 3 ), …..etc. Remember; 1 cm 3 = 1 mL 1 cm 3 = 1 mL
Remember this geometry? Volume of a cube is …. l x w x h i.e. 4cm x 5cm x 2cm = 40 cm 3 i.e. x (5cm) 2 x 10cm = 250 cm 3 Volume of a cylinder is …. r 2 h
Determining the Volume of an Irregularly Shaped Solid 22 mL 32 mL
Units of Density: –Mass is measured in g. –Volume is measured in mL or cm 3. –Density is mass / volume, (g) / (mL) (g) / (cm 3 ),so.. density is measured in: g/mL or g/cm 3 1 cm 3 = 1 mL 1 cm 3 = 1 mL
DENSITY - an important and useful physical property 13.6 g/cm 3 21.5 g/cm 3 Aluminum 2.7 g/cm 3 Platinum Mercury
Density of Gold: 19.30 g/mL Silver: 10.50 g/mL Aluminum: 2.70 g/mL Atoms of some elements are more dense than others.
Sample Problem What is the density of 5.0 g of tin that has a volume of 1.2 mL? D = m / v = 4.2 g/mL D = ? m = 5.0 g v = 1.2 mL
Steps for Solving Problems 1.Write the shopping list: the unknown variable. (whats the question asking for?) all of the known variables. 2.Write the formula you will be using. 3. Calculate the final answer and include the units.
Sample Problem What is the density of 45.0 g of a liquid that has a volume of 62.5 mL? D = m / v = g/mL D = ? m = 45.0 g v = 62.5 mL
Variations of the Density Formula: D = m/v v = m/D m = v D Dv m
Sample Problem What is the volume of 21.0 g of tin? (Density of Tin = 4.2 g/mL) v = ? D = 4.2 g/mL m = 21.0 g v = m / D v = 5 mL
Sample Problem What is the mass of 20 cm 3 of tin? (Density of Tin = 4.2 g/mL) m = ? D = 4.2 g/mL v = 20 cm 3 m = v D m = 84 g = 4.2 g/cm 3 = 20 mL
Review: 3 methods of measuring volume: directly using glassware geometry (e.g. l w h ) water displacement (v f – v i )
Variations of the Density Formula: D = m/v v = m/D m = v D
1. Write the unknown variable. 2. Write all the known variables. 3. Convert all variables to similar units. 4. Write formula you will be using. 5. Calculate: Plug and Chug 6. Circle your final answer with correct units.