Question

section 2.3 chemical properties
(pages 54-58)
this section discusses chemical properties and describes clues that may show that a chemical change has taken place.

reading strategy (page 54)
relating text and visuals as you read, complete the table by finding examples of the clues for recognizing chemical changes in figures 19 and 20. for more information on this reading strategy, see the reading and study skills in the skills and reference handbook at the end of your textbook.

recognizing chemical changes
\

$$\begin{tabular}{|l|l|} \\hline clue & example \\\\ \\hline change in color & copper roof changing color from red to green when exposed to moist air \\\\ \\hline production of gas & \\\\ \\hline formation of precipitate & \\\\ \\hline \\end{tabular}$$

observing chemical properties (pages 54-55)

1. circle the letters of the compounds formed when a candle burns.

a. paraffin
b. water
c. carbon

1. what is a chemical property?

1. is the following sentence true or false? flammability is a materials ability to burn in the presence of carbon dioxide.

1. the property that describes how readily a substance combines chemically with other substances is \\_\\_\\_\\_\\_\\_\\_\\_\\_\\_\\_\\_\\_. circle the correct answer.

reactivity malleability conductivity

1. circle the letter of each property that is a chemical property.

a. hardness
b. density
c. flammability

Explanation:

Identify candle combustion products

We need to determine which compounds form when a candle burns. A candle is made of paraffin wax (a hydrocarbon). When it burns in oxygen, it undergoes combustion to produce carbon dioxide and water (\(\text{H}_2\text{O}\)), which is a Chemical Compound. Paraffin is the starting reactant, and carbon (soot) is an element, not a compound. Thus, the compound formed is water.

Define chemical properties

We define what a chemical property is. Using our understanding of the Properties of Matter, a chemical property is any characteristic of a substance that can only be observed or measured during a chemical reaction, which changes the substance's chemical identity.

Evaluate flammability statement

We analyze the statement: "Flammability is a material's ability to burn in the presence of carbon dioxide." Flammability is actually a material's ability to burn in the presence of oxygen, not carbon dioxide. Carbon dioxide is typically used to extinguish fires. Therefore, this statement is false.

Identify chemical combination property

We look for the term describing how readily a substance combines chemically with other substances. Reactivity is the chemical property that describes how easily a substance undergoes a chemical reaction with other materials. Malleability and conductivity are physical properties.

Classify properties of matter

We classify the given options as physical or chemical properties. Hardness and density are physical properties because they can be measured without changing the substance's identity. Flammability is a chemical property because observing it changes the substance into new materials.

Answer:

Question 1

b. water

Question 2

A chemical property is any characteristic of a substance that describes its ability to change into different substances, which can only be observed by changing the chemical identity of the substance.

Question 3

False

Question 4

reactivity

Question 5

c. flammability