Conceptual Chemistry Density Preview 2016 Send to Gene Easter

by June 20. 2016Put your email here so I can email it back. Thanks. Name your attachment your last name and Density. Thank you.

Name______Grade______

  1. Create a concept map for density put the major concepts in circles near the top and minor ones below. Connect the circles with descriptors. Descriptors go on the arrow lines.

This just a start for you. Change it any way you want. More correct branching the better. 20 correct branches is good. Gene

is

divided

units of measurement

2. My meter stick has a volume of 120 cm3 and a mass of 60 grams.

A. I want you to divide the mass by the volume of my meter stick and tell me what is the meaning of this division and you can’t use the word per in your answer. A / is per. What use can be made of the concept?

B. Also divide the volume by the mass and tell me what is the meaning of this division. Also you can’t use the word per in your answer. Who would use such a concept?

3. How are density of a substance and concentration of solutions similar and different? How does density relate to the everyday world?

  1. Discuss how you would approach teaching the concept of density to your students. Please list activities and pre and post assessments and the grade level of your students.

I would teach ___ grade.

  1. Plastics make up 30% of city solid waster by volume. There are six types of plastic that can be recycled, but these different types cannot be melted together to create new plastic products. For this reason, most plastic containers and other disposable plastic products are marked with a number 1-6 which appears inside the recycle symbol and indicates the plastic type.

Your task here is to design an activity for your students to separate the 6 plastic types using density.Pay close attention the density ranges of each material.

NumberPlastic(chemical name) Density(g/cm3) Example product

1polyethylene terphthalate (PETE)1.35-1.39soda bottles

2high density polyethylene (HDPE)0.95-.97milk jugs

3polyethylene1.16-1.42Ziploc bag

4low density polyethylene (LDPE)0.92-.94 catsup bottle

5polypropylene (PP)0.89-.91 sour cream container

6polystyrene (PS)1.04-1.07clear deli containers

Liquids to use: Name chemical Density(g/cm3)

Water( 25 oC)0.997

ethanol0.789

corn oil0.925

glycerol1.26

corn syrup1.38

solution 33%sugar1.12

2:1 isopropyl alcohol/water0.95

6. A graduated cylinder was weighted dry, then filled to the 25 cm3 mark with a liquid and weighed again. From the data below calculate the density of the liquid. Show your work. Be careful of significant figures.

Mass of the dry graduated cylinder –28.31 g

Mass of the cylinder with the liquid—48.43 g

Volume of the liquid in the cylinder—25.0 cm3

Be careful of significant Figures

7. Solids and Holes

Willard had a thin, uniform solid piece of material. He placed the material in water and it floated. He took out the material and punched holes all the way through it. What do you think Willard will observe when he puts the material with holes back in the water? Circle your prediction.

A. It will sink.

B. It will barely float.

C. It will float the same as it did before the holes were punched in it.

D. It neither sinks nor floats. It will bob up and down in the water.

Explain your thinking. Describe the “rule” or reasoning you used to make your prediction.

8. Two ice cubes are floating in water:

After the ice melts, will the water level be:

  1. Higher?
  2. Lower?
  3. Same?

9. What is the reason for your answer to question 8?

  1. Water is more dense in its solid form (ice).
  2. Water molecules displace more volume than ice molecules.
  3. The water from the ice melting changes the water level.
  4. When ice melts, its molecules expand.
  5. The weight of the water displaced is to the weight of the ice.

Gene Easter 2015_____