We repeated thus experiment twice with each fuel, using clean water each time. Results Temp Of Water Alcohol Mass of alcohol Energy In Energy Out Before After Before burn After burn 26 46 Methanol 173.88 163.02 246386 408 25 45 Ethanol 163.98 162.80 35651 408 25 45 Propanol 157.73 156.82 30651 408 25 45 Brutanol 168.52 167.82 25,313 408 Calculations for energy in Calculations for energy out (Mass x enthalpy for substance) (Mass of water x enthalpy for substance x Mole temperature) 10.86 x 726, 000= 246,386.25 100 x 4.18 x 20= 408 32 1.18 x 1367, 000= 35,066.5217 46 0.91 x 2021, 000= 30,651.8333 60 0.7 x 2676, 000= 25,313.5135 74 Efficiency calculations Methanol = 408 x 100 = 0.16% Propanol= 408 x 100= 1.33% 246,386 30651 Ethanol= 408 x 100= 1.16% Bruntanol= 408 x 100= 1.61% 35066 25313 Accuracy As we can see all
In fact, the wax itself is burning as a vapor or gas. Objectives 1. What happens to the candle when you light it? 2. Can you prove that the candle needs oxygen in order to burn?
Lab #5 – Exp #2: Evidence for Chemical Change Name: Period: 2 Date Due: 1/27/12 Lab Partners: ______________________ Objective: • To observe the types of evidence that indicate a chemical change has taken place. • Infer from the observation of chemical change that a new substance has been formed. Procedures: 1. In the 250ml beaker, make a water bath by heating until boiling approximately 125 ml of water. 2.
To the second, add 10% NaOH dropwise until the pH is 14. (To do this, add a couple of drops of NaOH to the tube; stir thoroughly with a stirring rod; then touch the stirring rod to a piece of pH paper to check your pH.) To the third, add 0.5% sodium bicarbonate solution to pH 9, and to the fourth, add 2% HCl to pH 2. Record your observations on the data sheet. Repeat the above tests using 2% casein solution.
BE READY WITH THE STOPWATCH. Record the time in the data table. Room Temperature Water: Fill beaker with 80mL of water. Use thermometer to record the temperature Drop Alka-Seltzer tablet in water. Measure the time it takes to completely dissolve.
UNCW Honors Chemistry Lab #1- Laboratory Safety and Boiling Water Date Started: 8/26/11__________________ Date Completed __________________ Purpose: To determine the temperature at which water boils. To learn how boiling and melting are physical changes. Background Information/Observations: 1) Explain the most common scenario when you observe water boiling. 2) Explain how you could change the rate at which water boils. 3) Explain how you could change the temperature at which water boils.
Reactants are substances that take part in and undergo change during a reaction. Products are substances that is formed as the result of a chemical reaction. Another concept that was introduced with this lab was stoichiometric ratio which is concerned with, involving, or having the exact proportions for a particular chemical reaction. Exothermic was also a concept introduced in the lab which is a reaction or process accompanied by the release of heat. And limiting reagent which is the reactant that is completely consumed when a reaction is run to completion.
4. The products of a burning candle are carbon dioxide and water. 5. wax(vapor) + oxygencarbon dioxide + water Reactants Products Conclusion: From this lab, I learned that wax burns in a vapor state. Fire requires fuel and oxygen in order to burn. The products of a combustion reaction are carbon dioxide and water.
Heat is released when combustion occurs in the calorimeter, causing a rise in the temperature of the water. The change in temperature can be used to calculate the amount of heat energy. Materials (Experiment A + Experiment B) * Thermometer * Glass stirring rod * Styrofoam cover * 400 mL beaker * Water * 2 Polystyrene cups * Unknown metal * Test tube * Stopper * 50 mL of HCL * 50 mL of NaOH Procedure Part A
Coal hypothesis = It activated carbon is added to a beaker with 100mL of water, then it will increase the pH over 48 hours. 2. Based on the results of your experiment, would you reject or accept each hypothesis that you produced in question 1? Explain how you determined this. a. Pyrite hypothesis accept/reject = I would accept the hypothesis, seeing as how the pH did in face lower from 6 to 2. b.