A voltmeter was used to measure the electrical resistance of different solutions. * Experiment and Observation: The plastic and glassware used in this experiment was thoroughly washed with hot water and rinsed with distilled water. * * Part I: Preparation of Standard Phosphate Solutions 1. 1.0 ppm standard: 1.00 mL of 10.0 ppm phosphate solution was placed in a 25 mL graduated cylinder and diluted to exactly the 10 mL mark with distilled water then poured into a plastic cup labeled 1. Cylinder was rinsed with distilled water.
Abstract In this experiment we are explored the simple calorimetric estimate for the enthalpy of combustion of different alcohols. Our aim is to find out which alcohol is most efficient. Method First of all we drew up a table – this was what we used to record our results in. We then measured 100cm3 of water into a measuring cylinder and poured the water into steel we then recorded its temperature. We selected a spirit burner and recorded the name of the fuel into our table; we also included the mass of the whole burner.
Hydrate Lab The purpose of this lab is to analyze the percent water in a crystalline hydrate and to indentify the hydrate from a list of possible unknowns. The solid hydrate will be heated to remove the water, and the percent can be found by measuring the mass of the solid before and after heating. The hydrate will be indentified by comparing the percent water in the hydrate with the percent water calculated for the possible unknown. Before the lab there are pre-lab questions: 1. Describe the three general safety rules for working with a Bunsen burner.
(As you can guess, different fuels begin burning at different temperatures.) Heat or ignition sources lift fuel (combustible material) to its activation energy to start the fire. The fire generates heat which sustains the chemical reaction; the blaze continues and spreads. Some firefighting tactics shield the fuel from air (oxygen) to extinguish the blaze. Carbon dioxide fire extinguishers expel a cold fog of CO2 that cuts a fire off from its air supply.
Observe the color change while it is being heated. After observing the color change, find the mass and moles of the hydrate. Then find the mass and moles of the water eliminated. And lastly find the mole ratio of water to hydrate. For part 2, do the same thing as part 1 except use an unknown hydrate and calculate the percent mass of water in an unknown hydrate.
The question is, how can you determine which liquids have a strong surface tension and which have a weak surface tension? An example of a liquid that has a unique, strong surface tension would be H20, water! Research suggests that water has a high surface tension because of their unique hydrogen bonds. Hydrogen bonds have, without a doubt, the strongest intermolecular attractions. According to Science Buddies in the article Measuring Surface Tension of Water with a Penny, water “molecules at the surface experience a net force pulling them inward” (2007).
Abstract The purpose of the experiment was to identify unknown ionic compound #. After many tests, the unknown was identified as sodium chloride. The cation (Na+) was determined by having a yellow/orange color flame test. The anion (Cl-) was determined by the chloride anion test when the unknown test solution showed a positive test for chloride. The synthesis of NaCl further identified the ionic compound by reacting sodium hydroxide and hydrochloric acid and obtaining solid sodium chloride.
Water would not change in mass because it is isotonic to its surrounding. By inserting these six dialysis bags filled with 25 mL of each solution into beakers of distilled water, we were able to see if there was the process of osmosis, if any. Before putting the six different dialysis bags into the solution of distilled water, we meticulously measured the mass of each bag. This was critical because we needed the initial mass in order to find the percent change in mass. After waiting for 30 minutes sharp, we measured the bags again and saw significant increases in mass for five out of the six dialysis bags.
In the experiment a secondary alcohol (cyclohexanol) is heated with acid (phosphoric acid). A carbocation is generated by the loss of water from cyclohexanol because of the protonated alcohol. Loss of hydrogen ion from the carbocation will give the desired alkene (cyclohexene). Fractional distillation is used to separate liquids that have different boiling points that are relatively close together. By using this method of distillation a mixture is heated to a temperature at which several fractions of the compound is evaporated the distillate is then condensed and collected.
Experiment 2 Time | Observations | 5 minutes | Bubbled like sugar | Once salt water was added | Turned soapy white and thick | Equation: METHOD 1) Put 2 cm3 of castor oil into a 250 cm3 beaker and add 10 cm3 of 5mol.dm-3 sodium hydroxide from a measuring cylinder. (Take care when measuring this out and adding it to the beaker to avoid any drips and spills.) 2) Heat the mixture gently over a tripod and gauze, STIRRING CONSTANTLY with a glass rod (otherwise the mixture erupts). Allow to simmer (boil gently) for 5 minutes. Steady the beaker using