Ch. 2: “Matter”

Section 2.3 Review: “Properties of Matter”

1. Classify the following as either chemical or physical properties:

a. is shiny & silver

physicalb. melts easily physicalc. burns in air chemical

d. has a density of 2.3 g/cm3

physicale. tarnishes in

moist air chemical

2. Describe several uses for plastic, & explain why plastic is a good choice for these purposes. Strong, rigid plastic can be used

in cases for electronic devices, such as CD players.

Flexible, transparent plastic can be used as food wrap.

3. Classify the following as either a chemical or physical change:

a. ice melting in a drink

physicalb. sugar added to

lemonade physical

c. mixing vinegar & baking soda to generate bubbles

chemicald. plants using CO2

& H2O to form O2

& sugar chemical

4. Explain why changes of state are physical changes.The composition of the substance does not change when it changes state.

5. Categorize the following as either absorbing or releasing energy.

a. solid CO2 going to CO2 gas absorbedb. rubbing alcohol evaporating absorbedc. aluminum solidifying in a mold releasedd. chocolate melting absorbed

6. Calculate the density of a rock that has a mass of 454 g & a volume of exactly 100 cm3.

D = m/V D = 454 g/100 cm3

D = 4.54 g/cm3

7. Critical Thinking

Q: You need to build a raft. Write a paragraph describing the physical & chemical properties of the raft that would be important to ensure your safety. You are not limited to the properties discussed in this chapter.

A: Physical properties could include a density less than water, enough strength to not bend or break when a load is placed on it, & insolubility in water. Chemical properties could include not reacting with water or not burning.