CK-12 Physical Science Concepts - For Middle School

http://www.ck12.org Chapter 2. Matter

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/117719

1. What is dry ice? What gas is used to make dry ice?


2. In making dry ice with a fire extinguisher, why is it necessary to have a bag to collect the dry ice?


3. How can dry ice be changed back to a gas?

Review

1. What is deposition, as defined in chemistry?


2. Describe an example of deposition in nature.


3. Tom, pictured in theFigure2.47, started to scrape frost off his windshield before driving to school on a
   cold morning. Then he decided to let the car’s defroster do the work for him. What conditions caused the
   windshield to become covered with frost, and how does the defroster clear the frost from the windshield?

FIGURE 2.47