A chemical reaction is a process that involves the rearrangement of the molecular or ionic structure of a substance. In the hot pack/ cold pack experiment a chemical reaction occurred. We were trying to find a temperature change where there was a rearrangement of atoms in a substance (substance change). A temperature change, color change, precipitate formation, odor, or change in acidity indicates that a chemical reaction has occurred. There was a temperature change which means that there was a chemical reaction. In the experiment, we had to decide if the substances used in the hot pack were endothermic or exothermic by the decrease or increase in temperature. Heat can be either released or absorbed. When heat is absorbed it …show more content…
The substances that we were supposed to choose from are : Sodium Bicarbonate, Calcium Chloride, Sodium Chloride, Magnesium Sulfate, Sodium Nitrate, and Sodium Thiosulfate. Our claim was that Sodium Bicarbonate , Calcium Chloride, and Potassium Chloride would make an economical hot pack. We then began to gather our materials for the experiment: ziploc quart-size bag, ziploc gallon-size bag, temperature probe, 2 oz. jar, beaker with water, Sodium bicarbonate, Calcium chloride, and Potassium chloride. We then began to test our experiment with the following procedures. First, fill the quart-size bag with 100 milliliters of water. Second, put 10 grams of Sodium bicarbonate into the same bag. Third, mix together and take the temperature of the water in the bag and record data. Fourth, get a new quart-size bag and fill it with 100 milliliters of water. Fifth, put 10 grams of Calcium chloride into the same bag. Sixth, mix together, take temperature of the water in the bag, and record data. Seventh, get a new quart-size bag and fill it with 100 milliliters of water. Eighth, put 10 grams of Potassium chloride in the same bag. Ninth, mix together, take temperature of the water in the bag, and record data. Tenth, calculate the change in temperature for each substance. Eleventh, determine if substances are an exothermic or endothermic reaction.
Thermodynamics is essentially how heat energy transfers from one substance to another. In “Joe Science vs. the Water Heater,” the temperature of water in a water heater must be found without measuring the water directly from the water heater. This problem was translated to the lab by providing heated water, fish bowl thermometers, styrofoam cups, and all other instruments found in the lab. The thermometer only reaches 45 degrees celsius; therefore, thermodynamic equations need to be applied in order to find the original temperature of the hot water. We also had access to deionized water that was approximately room temperature.
Cu (aq) + 2NO3 (aq) + 2Na+ (aq) + 2OH- (aq) → Cu(OH)2 (s) + 2Na+ (aq) + 2NO3(aq)
The data which was collected in Procedure A was able to produce a relatively straight line. Even though this did have few straying points, there was a positive correlation. This lab was able to support Newton’s Law of Heating and Cooling.
During an intense game, athletes need a way to soothe their acute injuries leading them to the instant cold packs in their team’s med kit as fans huddle under blankets clutching hot packs between frigid fingers. What these two groups don’t realize is that they are utilizing chemical reactions in order to either expel or absorb heat. Chemical reactions that were discovered and utilized by inventors to create the very packs they are using. The chemicals inside each respective pack have various properties and applications that make them useful in their thermochemistry reactions. The compounds used are salts including sodium acetate and calcium chloride for hot packs and ammonium nitrate for cold packs.
Specific heat capacity of aqueous solution (taken as water = 4.18 J.g-1.K-1). T = Temperature change (oK). We can thus determine the enthalpy changes of reaction 1 and reaction 2 using the mean (14) of the data obtained. Reaction 1: H = 50 x 4.18 x -2.12.
Chemical kinetics is a branch of chemistry that involves reaction rates and the steps that follow in. It tells you how fast a reaction can happen and the steps it takes to make complete the reaction (2). An application of chemical kinetics in everyday life is the mechanics of popcorn. The rate it pops depends on how much water is in a kernel. The more water it has the quicker the steam heats up and causes a reaction- the popping of the kernel (3). Catalysts, temperature, and concentration can cause variations in kinetics (4).
The purpose of the lab was to show the effect of temperature on the rate of
During this reaction the solution gained heat. This is what we were monitoring. The reason why the solution gained heat is because the reaction lost heat. Energy is lost when two elements or compounds mix. The energy lost/ gain was heat. Heat is a form of energy as stated above in the previous paragraph. The sign of enthalpy for three out of the four reactions matches what was observed in the lab. For the last reaction, part four, the reaction gained heat not the solution like parts one through three. The negative enthalpy value for part four indicates that the reaction gained
Freezing is a big part of this experiment. When liquids freeze it becomes ice, the molecules begin to form a crystal lattice, which pushes them apart. However, when a liquid is frozen it has taken up to 9% more room than it did when it was a liquid. Another word for freezing is solidifying. But, the purity of a compound can influence at when the liquid to solid change takes place. Most substances freeze at the exact same temperature that they melt. But did you know that hot water freezes faster than cold water? As the water warms up it becomes less dense, the hydrogen bonds stretch and the molecules move farther apart when these hydrogen bonds stretch they allow the covalent bonds to shrink and release their energy. This is equivalent to cooling. So, hot
In this lab, it was determined how the rate of an enzyme-catalyzed reaction is affected by physical factors such as enzyme concentration, temperature, and substrate concentration affect. The question of what factors influence enzyme activity can be answered by the results of peroxidase activity and its relation to temperature and whether or not hydroxylamine causes a reaction change with enzyme activity. An enzyme is a protein produced by a living organism that serves as a biological catalyst. A catalyst is a substance that speeds up the rate of a chemical reaction and does so by lowering the activation energy of a reaction. With that energy reactants are brought together so that products can be formed.
Lab 4: Energy Conservation: Hot Stuff!! The purpose of this experiment is to try to find the original temperature of the hot water in the heater using the 60 degrees C thermometer. Use your 60°C thermometer, and any materials available in your laboratory, to determine the temperature of the water in the coffee pot. During this experiment we calculated the original temperature of a heater after it had been cooled down, and we did this by measuring hot, cold, and warm water, with a thermometer that had tape covering 60 degrees and up.
- Temperature was measured after and exact time i.e. 1 minute, 2 minutes, 3 minutes.
In order to understand this experiment, some background information was needed. For example, a person must understand what a melting point and what a freezing point is. A freezing point is defined as a temperature at which a liquid changes into a solid. A melting is the opposite of the freezing point. It is defined as a temperature at which a solid, turns into a liquid. That in order to freeze pure water, the water must reach a temperature of less then 0˚Celsius. They also must have knowledge that in order to change pure water (in the solid form) to a liquid, that solid must reach a temperature above 0˚Celsius.
Methodology: A plastic cup was filled half way with crushed ice and mixed with four spoonfuls of 5 mL of sodium chloride. A thermometer was quickly placed inside the cup to take the temperature and the