Exothermic Salts Lab Report

An instant cold pack is a device which is composed of 2 sacks, one which contains water, and the other with another chemical. When the user wishes to activate the cold pack, she squeezes it, and breaks the boundary between the water and the chemical. This causes an endothermic reaction as the water dissolves the chemical. The reaction then lowers the pack’s temperature by absorbing heat from the surroundings. Cold packs typically utilize the chemicals ammonium nitrate, calcium ammonium nitrate, or urea. A cold pack using ammonium nitrate will typically hit a low of 1.67℃ for 10 to 15 minutes. However, for the purposes of the first portion of the experiment, the chemicals being tested were ammonium chloride, sodium chloride, and calcium

When the final mass was measured the excess water in the potato cube might have not been completely removed, thus it adds to the final mass of the potato cubes. This acts as a major error because it gives an inaccurate representation of the actual percentage change in mass of the potato cubes, also while measuring the mass of each cube of potato; the value fluctuated and was not consistent.

In the third stage of this experiment, the density of a liquid was determined and compared to known standards. A 100ml beaker was filled to about half-full with room-temperature distilled water. The temperature of the water in ◦C was recorded in order to compare to known standards later. A 50ml beaker was then weighed on a scale in order to determine mass and recorded. A sample of the distilled water with an exact volume of 10ml was then placed in the 50ml beaker using a volumetric pipette. The 50ml beaker with the 10ml of water was then weighed again and the initial mass of the beaker was subtracted from this mass to obtain the mass of the 10ml of water. With the volume and the mass of the water now known, density was calculated using d = m/V and recorded in g/ml. This process was then repeated to check for precision and compared to standard values to check for accuracy. Standard values were obtained from CRC Handbook, 88th Ed.

Overall, we were able to discern that calcium chloride would serve as the most effective ionic solid within a hand warmer. Foremost, it served as one of the most effective solids in regards to heat production. The reason being, as seen from our calculations, when one places 10 grams of any of the ionic solids tested in the experiment inside a hand warmer containing an inner pouch of 40 mL of water, calcium chloride has the second greatest expected increase in regards to the heat of the solution. Also, these two compounds have the greatest heat of solution of all the tested ionic compounds. The only ionic solid which trumps calcium chloride in this category, would be lithium chloride. However, due to lithium chloride greater toxicity in comparison to calcium chloride, one will have to deem the latter as our most effective hand warmer. This can be seen as skin must be immediately washed with water when it comes into contact with lithium chloride, such measures are not necessary with the slightly hazardous calcium chloride. Additionally, lithium chloride has the greater personal protection rating in comparison to that of calcium chloride from their respective MSDS sheets, with a rating of E to C. Thus, the former requires a greater degree of protection on the part of the users to prevent harm. Since hand warmers will come into contact with the hands of users, and there is a potential of a leak, calcium chloride is the safest option, as even in the case of a leak, the safety of

One error for the experiment could be from the popping and spritzing of the hydrate when heating it, which could have caused a slight decrease in mass of the whole compound. Since some of the hydrate spritz out of the crucible, the mass decreased. This directly affected the results of the experiment because the mass that spritzed out of the crucible caused the mass to be weighted differently when remeasured on the scale. Another error of the experiment was that there was some hydrate that stuck to the stirring rod when stirring the hydrate.

The variation of data on the graph may be the result of systematic or random errors. In this experiment, volume is the independent variable which affected the mass calculated by the weighing balance. Figure 1 also pointed out the precision of the three glassware used to measure the volume. Pipette seemed to be the most precise instrument to use for measuring volume because most of the Diet Sprite and all of the regular Sprite densities were calculated very closely. Burette was also accurate but not as precise as pipette. There are some points on burette chart that go very high or very low. This is probably because the volume was not measured accurately. Another error that altered the data was the beaker used to measure the mass might have some solution in it already and thus mass of the solution increased. Mistakes such as wrong measurement or calculations also affected the graph. Pipette is the most precise because almost all the points are close to each other whereas graduated cylinder is the least precise because the data is vastly spread on the graph 1.

The weight of each 50ml beaker (used for weighing the mass of dissolved Potassium chloride after the evaporation of water) should be recorded. If the experimenter were to weigh the mass of one beaker and take it as a default mass, the latter may be a source of error.

In this experiment, we investigate the change in temperature caused by adding a chemical substance into the water and dissolving it. The results recorded in the table below show that our hypothesis is correct.

It’s freezing cold outside, Can you guess what time of the year it is?....Yes it is winter. Doesn’t onee seem to get cold during the winter? Well think about the coldest part of one’s body that one would really like to keep warm...their hands! Peoples hands are always screaming for warmth and protection. Hand warmers are the key to that cold lock. This project looks into the history of hand warmers. It also tells about what’s in a handwarmer that makes it so beneficial. It shows the different crystals that heats the hand warmers. Have you ever thought about what’s in a hand warmer that makes it turn hot and keeps people’s paws nice and cozy? Well if you have, then this is the project that you should be reading. If you haven’t, aren’t you wondering

The mean temperature of substance 2 for room temperature was 20°C. Substance 2 dissolved easily in the water. The mean temperature for substance 2 in colder water was 6.25°C, and most of the powder dissolved. However, some of it sank, leaving us to think both substance 1 and 2 were supersaturated in the cold water. The average temperature of substance 3 for room temperature was 23.5°C.

Introduction The ability to maintain a relatively stable core body temperature regardless of the external environment is referred to as homeothermy (Wooden and Walsberg 2002). It is an evolutionary feat that has enabled endotherms to thrive in harsh conditions past and present. In colder climates endotherms may grow fur to aid with insulation. However, there is a trade-off.

As shown on the graph, the temperature of the water without salt is constantly higher than the water with salt, until 2:30. This is when the temperature of the water with salt overtakes, which relates to the previous relationship of the presence of salt and the manner in which temperature rises. Difficulties There were multiple difficulties throughout the planning and conducting of the experiment. One of these difficulties was Improvements

To design and create an effective instant cold pack by using selected chemicals to produce an endothermic reaction. The reaction is required to produce cold enough temperatures to support an injury and remain cold over a period of time. To be classified as an effective instant cold pack it needs to remain at a reasonable temperature (safely regulated output: 7-11°C) for 20 minutes. 10,11

Post experiment values of fluid’s specific weight yielded errors for each experiment, with the most significant error in calculating the

In class this year we investigated sodium reactions in three entirely different experiments. In the first of the experiments, our teacher drop sodium metal into a glass bucket of water and stood behind an extremely thick piece of plastic for protection. The sodium reacted as soon as the protective layer around the metal dissolved into the water and then the sodium exploded and caught fire, this created heat and light. This reaction made sodium hydroxide and hydrogen gas (NaHO and H). In the second of the experiments, we all split up into groups of around three or four and went over to our own separate benches for each group. We all then took turns to pick up the sodium with metal tongs and placing it in the blue part of the Bunsen burner flame