During the electrolysis, a gray solid formed on the negative wire of the battery and the dark red solution formed at the positive wire of the batter. Account for this in terms of the positive and negative ions. Iodide ions have the symbol I-, indicating they are negatively charged, which cause them to be attracted to be something with a positive charge, which is why there was a red-brown solution at the positive end. Zinc ions have the symbol Zn2+, indicating a postive charge, which cause them to be attracted to something with a negative charge, which is why a grayish solid formed at the negative wire. 3.
d) The reactions are complete when the bubbles stop forming. e) Zinc, Hydrogen, Copper Challenge What is the chemistry-based reason for this peculiar construction of a penny? Zinc is too reactive to for the coin to be totally made out of zinc. The copper is not as reactive and is a protective
He built a rectangular box, insulated and lined the inside with black cloth, and covered the top with glass. Sunshine penetrated the glass cover and was absorbed by the black lining, which converted the light into heat. Sunshine can pass through glass, but heat cannot so Saussure’s hot-box effectively captured heat. The hot-box was the prototype for future solar collectors (Perlin, n.d.). In the 1800s, the first solar water heaters on record were developed.
| Centrifuge: used to isolate the solid from the solution | . Focus Questions: When acidified water is not used in the zinc and iodine synthesis, zinc hydroxide is formed. How can it be identified based on the amphoteric nature. When zinc and iodine react without the presence of acetic acid in the water, zinc hydroxide forms. This is evident because the substance tested positive for both the acid test and the base test for zinc hydroxide.
6. Is it possible to light a candle without touching the flame directly to the wick? Why or why not? Materials • candle • matches • safety goggles • lab handout & pen • ruler • watch glass • 400 mL beaker • CO2 indicator solution (limewater) • 50 mL beaker (for indicator) Procedure My lab partner and I performed a series of experiments to investigate the chemistry of the burning of a candle. The teacher provided the following chemical equation to describe the burning, or combustion, in the candle: Hydrocarbon fuel + O2 ( CO2 + H2O The candle we used was a small, white emergency candle about 3.5 cm tall.
We thought that a pH level of 3 would be the optimal pH level for the enzyme catecholase and its substrate catechol to react in. There was no prior knowledge on the effect of pH levels on catecholase and catechol. The results of the experiment did not confirm this hypothesis; instead the hypothesis was rejected by the results of the experiment. The results showed that tube 1 had the slowest rate of reaction, and actually did not react at all. The results showed that tube 2 had the fastest rate of reaction; this tube was exposed to the neutral pH of 7.
Also a very pale purple tint formed. Acid test: Added 2 mL of 1M NaOH- no Physical change was observed. Base test: Added 2 mL of .17M Acetic acid- No physical change observed. Table: Zinc (g) | Iodine (g) | Deionized water (mL) | Weight of boiling tube (g) | 1M NaOH(mL) | .17M Acetic acid (mL) | 2 | 2.01 | 5 | 40.73 | 2 | 2 | 2. Answer to focus question: Since it is amphoteric, it will act as an acid if reacts with base and act as a base when reacts with acid.
Jose Flores 6th period 1-27-14 LAB REPORT Introduction: A substance can conduct an electrical current if it is made of positively charged and negatively charged particles that are free to move about and is called a conductor. The purpose is to figure out conductivity of substances and to check which one conducts electricity. The hypothesis is that sucrose would be the only one that could not conduct out of the other six solutions. Materials: The materials used in this lab where six solutions , napkins, 2 pairs of gloves, 2 cups (1 cup with distilled water and 1 cup with solid NaCI) and a conductivity meter. The six solutions are sodium chloride, hydrochloric acid, sodium hydroxide, acetic acid, ammonia and sucrose.
Physical b. Pulp-free orange juice is prepared by filtering most of the pulp from fresh orange juice. Physical c. The compound glycerin, which is used in lotions, is formed as a byproduct during the preparation of biodiesel fuel from waste restaurant oils. Chemical 4. Identify each of the following as a substance or a mixture: (3 points each, 12 points total) a. helium gas that is used to fill a balloon Substance b. the juice that is squeezed from an orange Mixture c. distilled water Mixture d. carbon dioxide gas Mixture 5. An advertisement for shampoos says that it is pure shampoo, with nothing artificial added.
In this lab, two different titrations were performed with three different antacids to determine which brand is the most effective at the cheapest price. The antacids were ground up separately and approximately 0.2 grams of it was placed in a flask. Methyl Orange, an indicator, and a stir bar were added into the flask. The flask was then put on a stir plate which was under a buret with 0.1M hydrochloric acid. The acid was poured into the flask until there was a permanent pink colour.