Lab10 RUBRIC

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Front Range Community College *

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102

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Chemistry

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Dec 6, 2023

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Lab 10: Bonding and Properties of Water Nathaniel Morales Nov 16, 2023

Chemistry of Life: Bonding and Properties of Water Purpose Statement: The purpose of this lab was to investigate the bonding and properties of water through various experiments, including solubility, adhesion and cohesion, density and miscibility, and heat capacity. Pre-laboratory Questions 1. Is sodium chloride an ionic compound or a covalent compound? What happens to the atoms in NaCl when the compound is dissolved in water? Sodium chloride (NaCl) is an ionic compound. When you dissolve table salt (NaCl) in water, the salt breaks into two ions: sodium (Na+) and chloride (Cl-). The water molecules surround and separate these ions, creating a saltwater solution. 2. Is sucrose, C 12 H 22 O 11 , an ionic or a covalent compound? What happens to the sucrose molecules when this solute is dissolved in water? Sucrose (C12H22O11) is a covalent compound. When you dissolve it in water, the sugar molecules stay together, surrounded by water molecules. The bonds within the sugar molecules don't break, but water helps spread the sugar evenly in the solution. Unlike salt, sucrose doesn't turn into ions when it dissolves. 3. Make a prediction about the solubility of each solute in each solvent examined in Activity 1. You may find it useful to look up the chemical structure of each solute and determine the extent of its polarity. Water (H 2 O) Isopropanol (C 3 H 8 O) Sodium chloride (NaCl) Soluble Not Soluble Sucrose (C 12 H 22 O 11 ) Soluble Not Soluble Benzoic acid (C 7 H 6 O 2 ) Not Soluble Soluble

Chemistry of Life: Bonding and Properties of Water Observations Activity 1: Solubility In the initial trial, B1, I mixed sugar with water and stirred for around 30 seconds. However, it seems I didn't add enough water because some sugar remained at the bottom without dissolving completely. In the subsequent trial, B2, I used salt and water. The salt dissolved in a similar time frame, but it didn't dissolve as easily as the sugar. There was a slight difficulty in the dissolution process. Moving on to B3, when attempting to dissolve benzoic acid in water, it did not dissolve. Most of it floated on the water's surface, and some settled at the bottom, resisting dissolution despite various attempts. Contrastingly, in trial A3, where benzoic acid was dissolved in isopropanol, the solution easily dissolved in water with minimal stirring. Activity 2: Adhesion and Cohesion In all C trials, pepper was combined with isopropanol and settled at the bottom without any dissolution. It remained undissolved in any capacity. Moving to the D trials, where water was used, the pepper floated on the water's surface, displaying buoyancy. The presence of a wooden splint had no impact on the pepper in water. However, when the wood splint was coated with a small amount of dish soap, all the pepper was repelled towards the edges of the container. Interestingly, when the wood splint was dipped in isopropanol and pepper, the pepper exhibited no noticeable reaction. The most intriguing observation was in D3, the water and pepper trial. Here, the pepper appeared to come alive, actively moving away from the wood with the dish soap, creating a fascinating visual effect. Activity 3: Density and miscibility

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