Design Lab Water and Alka-Seltzer

The only dependent variable is the time the ice cubes take to melt. The controlled variables are the size of the ice cube, and the room conditions they melted in. Aim: To see which type of ice cube melts faster (the one with or without sugar).

However, the results of this experiment may not have been as accurate or precise as they

In this lab we tested how changing the content of the water affects the speed of the alka seltzer dissolving. My hypothesis was that the tap water would dissolve the tablet fastest, the salt water would be second fastest, and the sugar water would be the slowest. I was correct that the tap water would dissolve the fastest, but I was wrong in that the salt water would dissolve faster than the sugar water. I think that our results came out the way they did because of the amount of sugar and salt we put into the water. When we put the sugar and salt into the beakers, we came up with those measurements on the spot. After the salt and sugar had been added, the salt water was very cloudy, but you could barely tell the tap water from the sugar water.

I found out that both of my experiments were off by 0.46 and 0.13 but were remotely

Since Alka Seltzer is swallowed and reacts with stomach acid, the vinegar is in this experiment is substituting as the stomach acid. The principle of limiting reagents relates to this lab because

There were three different runs in order to have comparable data and to increase the validity of the experiment. The first run gave 39% of Sodium Bicarbonate. The second run gave 34% of Sodium Bicarbonate while the third one gave 39%, which is the same as the first run. The average percentage was 37% which is much lower than the manufacturer's percentage of 59%. The percent error came out to be -37%.

How does the dissolve rate of the Alka-Seltzer tablets change as the temperature of the water changes? The dissolve rate is being affected by the temperature of the water. Temperature is a measure of kinetic energy in molecules (NYU). The higher the temperature, the higher the kinetic energy. Energy is required to create a reaction. Molecules with more energy come into contact with each other more often. The molecules of the reactants have to come into contact with each other, so more energy in molecules result in faster dissolving time.

In this experiment the scientists are looking for how gas production is effected when different sized Alka-Seltzer tablets are put into water. The independent variable is the different sizes while the dependent variable is the amount of gas produced. A constant variable includes the same brand of Alka-Seltzer tablets, the volume of water and same starting temperature. Finally the scientist’s control variable is the first trial testing the whole tablet comparing its reaction time to each new piece.

Alka Seltzer is a medicine that acts as a pain reliever and an antacid. Antacids are used to help neutralize the acids in the stomach and help treat acid reflux, heartburn, indigestion, and gastritis. The tablets contain sodium bicarbonate (NaHCO3) and citric acid (C6H8O7). The sodium bicarbonate is a base that helps neutralize the acids in the stomach, mainly hydrochloric acid (HCl). It does this by the following reaction: Na3C3H5O7(aq) + 3HCl(aq) H3C3H5O7(aq) + 3NaCl(aq). When the tablets are dropped into the water, a reaction occurs in which water (H2O), sodium citrate (Na3C6H5O7), and carbon dioxide (CO2) are formed.

The range determined in the experiment is approximately 2 degrees above the actual melting point range, indicating some impurities in the final compound. According to the IR spectrum, the product obtained is quite pure. The peaks in the table above indicate the presence of a carbonyl, specifically the C=O bond of a cyclic ketone and also the sp2-hybridized =C–H bond of an alkene. There is no broad peak ranging from 3200 cm-1-3600 cm-1, which would indicate the presence of the -OH group of an alcohol. Thus, there is likely no presence of starting material in the final product. The percent yield above 100% indicates that some liquid (hexanes) used to recrystallize the product was likely still in the flask when the product was weighed.

Alka-Seltzer is used for heartburn and upset stomachs. It is pretty much vinegar and baking soda. The formula is C6H8O7 (citric acid) + 3NaHCO3 (baking soda) 3H2O (water) + 3CO2 (carbon dioxide) + Na3C6H5O7 (sodium citrate). Alka-Seltzer was first marketed in 1931 by Dr. Miles of Medical Company in Elkhart, IN. It can work by blocking the action of a substance in the body.

The experimental setup will be a pH meter placed inside each water bottle of water to check the acidity in each one, and it will be tested with a pH meter. The purpose of the investigation is to see which company of water bottles has the highest pH level. The independent variables are the different companies of water, the dependent variable will be the pH level of the water, and the controlled variable will be the pH meter, the computer and wires, the glass of water, and the distilled water.

For example, when dissolving the samples, too much liquid could have been added, affecting how saturated the solution was, and ultimately affecting the accuracy of the results. To prevent such an error, one could gradually add water and patiently mix the solution to make a saturated solution. Additionally, errors could have come from not making a solution as close to 1.0 M of the compound. In order to prevent this possible error, one could have calculated the volume of the water (in mL) needed to make the 1.0 M solution, which would result in having more precise results. Lastly, being that there are multiple calculations involved, being careful and observant in correctly recording the values could prevent simple

The accuracy of this experiment cannot be commented on as there is no ‘true value’ to compare the gathered results with however, if more results were to be collected the accuracy would increase. The precision of the experiment can be interpreted through the range of the values (min and max), as shown in the fig 4 the gap between the minimum and maximum is large which leads to believe that the data was low in precision. The validity of the experiment was moderate as the investigation carried out measured what it was supposed to measure however, not with the amount of accuracy that was

This equation resulted in being left with a negative final percentage error. Which was easy to fix, as it just had to be turned into a positive for the final answer. It is evident to see how the theoretical results increase each time approximately -620 KJ/mol. This is as each carbon chain increases so does the amount of bonds associated with it.