Check wall for updated grades as of midnight Check wall for updated grades as of midnight! ELEMENT QUIZ #2 tmrw Density HW (front & back) due tmrw Put page 28 on your density handout. Start a page 27 Cornell Notes: TOPIC: DENSITY OBJ: Manipulate chemical quantities using scientific conventions. ESQ: How can slope determine density of an object?

Density Density: ratio of mass to volume characteristic property that depends on the composition of a substance does not depend on the size of the sample  intensive physical property Intensive Extensive Color Length Boiling Point # of atoms Phase of matter (S, L, G) Mass

Density Column Smallest Density Increasing Density Largest Density

Density Column Practice!! Four liquids were placed in a graduated cylinder and they formed 4 layers – use colored pencils to color in the layers formed Five objects were then dropped into the density column. --Draw the objects on your column. Color Density (g/mL) Red 1.00 Green 0.75 Blue 1.10 Orange 1.25 Object Density (g/mL) 2.75 1.04 0.9 0.65

Equation D = m V D: density (g/mL or g/cm3) m: mass (g) V: volume (mL or cm3) D = m V

Example #1 What is the density of a material that has a mass of 15 g and a volume of 3 mL?

Example #2 What is the mass of an object if its density is 2 g/cm3 and its volume is 5 cm3?

Example #3 What is the volume of a liquid with a density of 2.0 g/mL and a mass of 8 g?

Think about this, genius!! A sample of water has a mass of 10.0 g and a volume of 10.0 mL 10.0 g D = 10.0 g / 10.0 mL m = _______ 10.0 mL V = _______ D = 1.00 g/mL

Example #4 Half of the water is removed. Predict what will happen to the density.

Terrific Tuesday Check wall for updated grades as of midnight! Get out density HW page Get out new piece of blank paper Use the ziploc of elements to quiz your table! ELEMENT QUIZ #2 tmrw Density HW (front & back) due tmrw PINK OUT PEP RALLY FRIDAY FOR S’MORES!!!

Percent Error Relative error equation Actual - Theoretical Absolute value (no negatives allowed) Percent Error = Experimental - Acceptedx 100 Accepted Theoretical

Let’s calculate the % error of a lab group that measured the dimensions for steel. The calculated values of the steel were: Mass of sample: 15.85 g Length of sample: 2.26 cm Width of sample: 1.80 cm Height of sample: 2.41 cm The true value for the density of steel is 7.8 g/cm3.

Percent Error = Experimental - Acceptedx 100%

Page 29 – Density Mini-Lab Section 1 (top ½ of page) Determine density of 5 liquids and 2 solids using tools provided on side counter Chemicals on back table – they stay put!!! No more than 10 mL of each liquid Section 2 (bottom ½ of page) Draw two 100 mL graduated cylinders Left  prediction Right  actual experiment ACTUAL PREDICTION