GENERAL CHEMISTRY (CHEM 1A) EXPERIMENT #3 PRELAB QUESTIONS AND ANSWERS 2025, Exams of Chemistry

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~~” GENERAL CHEMISTRY (CHEM 1A) EXPERIMENT #3 PRELAB QUESTIONS AND ANSWERS 2025 Prelab Questions 1. Define the terms dependent variable and independent variable. Look back at part 2 of last week’s experiment. What was the dependent variable and what was the independent variable? Explain. « Dependent variable: The variable being tested in a scientific experiment (depends on the independent variable). ¢ Independent variable: The variable that is changed or controlled ina scientific experiment. In part 2 of last week’s experiment, the dependent variable was Boron because it didn’t change, we always added 1 ml to the mixtures. The independent variables were PVA and Guar because we changed them either by increasing or decreasing them. 2. Define the terms quantitative measurement and qualitative measurement. Give an example of each type of measurement from the data you collected last week ¢ Quantitative measurement: Measurement based on numbers (can be counted). i. Example of quantitative measurement from the data | collected last week was length of stretchiness (in cm). ¢ Qualitative measurement: Measurement based on descriptions and concepts (smell, taste, etc). i. Example of qualitative measurement from the data | collected last week was or had to do with how sticky the mixture was. ii. 3. Imagine you are working for a toy company and you want to create a polymer that would be fun for a 6-year old to play with. Consider the items below, which will help you to design and measure your results efficiently. ¢ List five properties of cross-linked polymer mixtures that you could optimize to create a fun toy. i. Five properties of cross-linked polymer mixtures that | could optimize to create a fun toy are: 1. Stretchiness 2. Bounciness 3. Stickiness 4. Moldable 5. Softness « For each property, describe how you would quantitatively measure it. Blue White One Cleaned Item Chemically Regular Trash | Gallon Waste snCrOUshHy ang Contaminated Bucket put back in the Waste Bins locker Solutions of polymers a Solid polymer samples “ Used reaction cups Used plastic pipettes “ ~ Used Glassware Used weigh boats Used wooden sticks Used paper towels NE ATA