Lab 4: Determination of Percent by Mass of the Composition in a Mixture by Gravimetric Analysis Introduction Thermal gravimetric analysis is used to determine the percent by mass is used to determine the percent by mass of a component in a mixture. When a mixture is heated to an appropriately high temperature, one component in the mixture decomposes to form a gaseous compound. The mass of this particular component is related to the mass of the gaseous compound. In this experiment, the percent by mass of sodium hydrogen carbonate (NaHCO3) and potassium chloride (KCl) in a mixture will be determined. Experimental First, we weighed 2 samples, each has 1 gram of NaHCO3-KCl mixture Second, we put the samples in 2 crucibles (A and B) and weighed them.
(4 points) q = m × c × Δt Given: q=? m = 34.720g c = 4.18 j/(g x °C) Δt = 41.6°C - 25.2°C = 16.4°C q = (34.720g) (4.18 j/(g x °C) (16.4°C) q = 2380.13j You are trying to figure out the energy change of the water which is the surroundings in the lab. To do that you must take the mass of the metal, which for me was Aluminum, and multiply it by the heat capacity of the water, which was given, then multiply that by the change in temperature, which is the final temperature of the mixture
As stated by the results above, different fuels produced different amount of energy. According to the data, out of the four different fuels, Cheetos, Wax Candle, Ethanol and Cashew nut, Wax candle produced the most energy (J/g). During the process of the combustion of cashew, there is an error. The flame that is burning the cashew during the second trial is bigger than the other trials, taking less time in burning fuels, causing the results to be inaccurate. If I were to do this experiment again, I would change the number of trials to increase the accuracy of the results.
Philosophy Assignment #4 1. The Problem of Induction was first brought forth by David Hume, a considerably famous Scottish philosopher. The problem of induction is the difficulty in justifying universal generalizations with observation. For example, when we conduct an experiment to find the boiling point of water we take a fraction of all the water in the world at a given time. When we discover that our sample water has a boiling point of 100 degrees Celsius we assume all water boils at the same temperature.
Reactions Lab David Vaghari INSTRUCTOR: Dr. Chernovitz Monday, July 23, 2012 Oxygen Production Introduction In this lab, potassium chlorate will be decomposed producing oxygen gas and potassium chloride. The hypothesis is that the reaction will yield 3.916 grams of oxygen gas. Materials Test tube 10 grams potassium chlorate Bunsen burner Procedure Step 1. Obtain a test tube, place a 10 gm of potassium chlorate. Step 2.
Dr Khounsary explains an experiment using a fixed voltage and varying the temperature of the wire using a torch. The article further explains that the temperature coefficient of copper at 20 degrees C is .00393 and that a single degree of temperature change would increase the resistance of the wire by that amount. In the article regarding the Effect of Temperature on Conductivity (The Nuffield Foundation, 2006) the article describes how the conductivity of a wire decreases as it is heated. It provides an example schematic diagram for the test circuit and the use of Eureka wire instead of copper wire. A2a.
EXPERIMENT 11 Molar Mass of a Volatile Liquid DATA Run | UNKNOW | Mass of flask and foil(g) | 90.085g | Mass of flask and foil and condensed vapor (g) | 90.640g | Temperature of boiling water (˚C ) | 98˚C | Barometric pressure (torr) | 761mm Hg | Volume of flask (mL) | 140 mL | RESULTS Mass of unknown ( condensed vapor) | 0.555g | Volume of flask (vapor)(L) | 0.14 L | Temperature of vapor(k) | 371K | Molar mass of unknown (g/mole) | 118.380 g/mole | Advance Study Assignment 1) How would each of the following errors affect the outcome of this experiment? Would it make the molar mass high or low? Give your reasoning in three sentences or less in each case. a) The hole in the aluminum foil was quite large. if you were to have a larger hole in your aluminum cap, you would be losing vapor to the room.
Andrea Gurke #8 Period 3 Chem Traditional Chem Unit 10- Thermodynamics- Book chapter 10 Objective Objective 1- Can define and distinguish between heat and temperature Temperature: measure of random motion (average kinetic energy) of components in a substance Heat: Flow of energy due to a temperature difference Temperature | Heat | How fast atoms are moving | Amount of energy | Measure of avg. kinetic energy | Flow of energy due to temperature difference | Measure of amount of energy | Form of energy | Speed limit | | Objective 2- Can define Specific heat capacity Specific Heat- Amount of energy it takes to change temperature of a substance by 1 degree Celsius Low Specific heat= LESS time to heat up/cool down= less energy High specific heat= MORE time to heat up/cool down= more energy Formula = Q= SxMx▲T Objective 3- Can perform simple calculations using the calorimetry equation (q=sm▲t) Q=1251 J Q= SxMx▲T S=X 1251 J= (x)(35.2)(25) M=35.2 g 1251/880=880x T1= 0 degree C 1.42 g/J T2=25 degree C Objective 4- Can perform complex calculations using the law of conservation of energy | metal | water | S (J/ degrees C) | ? | 4.184 | Mass | 75025 | 100 | Ti | 99.3 | 22.4 | Tf | 32.9 | 32.9 | Q= SxMx▲T Qmetal+Qwater=0 Q= -Q metal | water | SxMx▲T | -(SxMx▲T) | S(75.25 g) (32.9-99.3) | -(4.184)(100)(32.9-22.4) | S(-4996.3) | -(4393.2) | S= | .879 | Objective 5- Understand endothermic and exothermic processes, including their definitions and values of enthalpy Exothermic= process when energy (as heat) flows OUT OF THE SYSTEM Ex: ice freezing Endothermic= process when energy (as heat) flows INTO THE SYSTEM Ex: boiling of water
Materials and Methods See attached sheet Results (1)In an attempt to find the relationship between the temperature of the reaction and the speed of the reaction, we measured the rate of the disappearance of color from the amylase/starch solution to indicate how fast the starch was used up. We found that very cold and very hot temperatures caused the reaction of the starch to proceed very slowly, if at all. The reaction that occurred at 37’C occurred the fastest resulting in a normal, or bell shaped curve centered around 37’C, as indicated by the graph below. Temperature in degrees Celsius Temperature in degrees Celsius Rate of Disappearance In Minutes Rate of Disappearance In Minutes (2)In an attempt to find the relationship between Amylase concentration and the speed of the reaction, we measured the rate of the disappearance of color from the amylase/starch solution to indicate how fast the starch was used up. We found that for the lower concentrations of amylase we
This principle is stated in Boyle's Law. Energy for the expansion is drawn from the expanding gas itself, thus causing a lowering of temperature in the gas. Steam engines and turbines, rockets, and internal combustion engines are powered by the expansion of gases. Bread rises in baking because heat expands the carbon dioxide gas it contains. Expansion of Liquids Unlike gases, liquids expand at different rates, depending on their composition.