Mystery Liquids - Mrs. Temple's Science Classes



Mystery Liquids

Key Words: Particle, Phase, Physical Change, Vapor

Getting Started:

1. In this activity, you will observe two mystery liquids that look exactly alike. In order to distinguish between the liquids, you must run a series of tests on them. You will take both qualitative data (data that describes characteristics people can perceive without making measurements and quantitative data (data that uses measurements).

Procedure:

1. Read the introduction and Challenge to Activity 35 “Mystery Liquids,” in your Student Book.

2. Water is by far the most common liquid substance on earth and the only one also commonly found in solid (ice) and gaseous (water vapor) phases.

3. Read “Part A: Observing and Predicting” of the Procedure for “Mystery Liquids,” in your Student Book. You will record your data on Student Sheet 35.1 “Comparing Physical Properties of Liquids,” that is attached to this packet.

4. Watch the LABsent video (found here: ). Your classmates performed this experiment to try to identify the substances. Watch the video to see the procedure being performed. Record the results in your data table. Not all of the Procedure is in the video. You will have to obtain any missing data from a lab partner or your teacher when you return to class. You will need this missing data to complete the Analysis Questions.

5. Read “Part B: Taking Measurements” of the Procedure for “Mystery Liquids,” in your Student Book. Each of your classmates measured different volumes of the liquids. The measurement for 10 mL are shown on Student Sheet 35.1 in Data Table 2. Calculate the “Mass of the liquid sample” and the “Density of liquid” and fill in the correct data.

6. Your teacher melted and boiled each liquid for the class. The data for each is listed in the table. Note: Liquid B will not solidify in the freezer therefore no melting point was measured.

Analysis Questions:

1. Review the data table “Some Properties of Five Liquids” in your Student Book.

a. Based on your data and the table “Some Properties of Five Liquids”, what could Liquids A and B be?

b. Why do you think so?

c. How certain are you?

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

2. In this activity you compared two liquids.

a. What properties and measurements were the most helpful in identifying the two liquids?

b. Explain your answer.

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

3. A liquid forms rounded droplets because of its degree of cohesiveness.

a. Which of the two liquids was more cohesive?

B Explain the observations that support your answer.

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

4. Why should you keep liquid samples capped or covered while studying them?

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

5. Which do you predict would evaporate more quickly at room temperature: methanol or acetone? (Refer to the data table “Some Properties of Five Liquids” in your Student Book.) Explain why.

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

|List 1 |List 2 |List 3 |List 4 |

|liquid |density |odor |property |

|solid |boiling point |feel |cohesive |

|gas |quantitative property |color |liquid |

|cohesive |color |temperature |comparison |

|phase |melting point |qualitative property |clear |

6. Look at the lists of words. Then, for each list, follow steps a, b, and c.

a. Look for a relationship among the words in List 1. Cross out the word or phrase that does not belong.

b. In List 1, circle the word or phrase that includes the other three.

c. Explain how the word or phrase you circled is related to the others.

d. Repeat steps a-s doe each of the remaining lists.

Explanation for List 1

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

Explanation for List 2

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

Explanation for List 3

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

Explanation for List 4

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

______________________________________________________________________________________________________________________

Comparing Physical Properties of Liquids

Be sure to include the units for the quantitative data you record in the data tables below.

Data Table 1: Observations of Two Unidentified Liquids

|Property |Liquid A |Liquid B |

|Qualitative data (observations) |

|Appearance | | |

|Smell | | |

|Feel on fingers | | |

|Behavior of a drop on plastic | | |

|Evaporation | | |

|Possible identities | | |

|Quantitative data (measurements) |

|Density | | |

|Boiling point |100 °C |78 ° |

|Melting point |0 °C |Not measured |

|Possible identities | | |

Data Table 2: Density Calculations

| |Liquid A |Liquid B |

|Volume of liquid sample |10mL |10mL |

|Mass of graduated cylinder |8.0 g |8.0 g |

|Mass of cylinder plus liquid |18 g |16.1 g |

|Mass of liquid sample | | |

|Density of liquid | | |

Issues and Physical Science - Student Sheet 35.1

-----------------------

© 2014 The Regents of the University of California

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download