3. Upon adding 20 drops of NaOH, a white precipitate was formed signifying acidic impurity. In the second NaOH mixture, about 20 drops were administered and no precipitate formed indicating that the ample is more pure than before. Data: Weight of flask = 75.10 grams Weight of the flask with solids =
Using the equation m = ΔTf/Kf , the molality of the unknown solution was found. Then, moles of unknown were calculated, which was used to calculate the average molar mass of unknown. Theory: After the experiment was completed, the data
In the round-bottom flask (100 mL), we placed p-aminobenzoic acid (1.2 g) and ethanol (12 mL). We swirled the mixture until the solid dissolved completely. We used Pasteur pipet to add concentrated sulfuric acid (1.0 mL) to the flask. We added boiling stone and assembled the reflux. Then, we did reflux for 75 minutes.
Introduction Alka-Seltzer has been on the market since 1931 and has helped to relieve indigestion and upset stomach. The tablets began to fizz and bubble when dropped into water. “The fizziness happens when baking soda (sodium bicarbonate) and citric acid react chemically in water. They yield sodium citrate, water and carbon dioxide gas, which causes bubbles.” Based on this information, we will measure the reaction time of AlKa- Seltzer dissolved in 200 ml of water at 3 different tempertures in the first portion of this experiment.
A mole is a unit of measurement that follows the rule of ; 1.00 mole = molar mass = 6.02 x 10^23 atoms/ ions/ molecules / formula units = 22.4 L of any gas at standard temperature and pressure. That formula was used to determine the mass of the anhydrated substance. A anhydrate is a substance with water heated out of it. The purpose of this lab was to determine how many moles of water are
A hot plate was placed under the ring stand. 50 mL of 3.0 M NaOH in a 250 mL beaker and a stir bar was placed in the beaker. The beaker with NaOH was placed on the hot plate and 3.75 grams of NaAlO2*5H2O was placed in the beaker. The temperature probe was placed in the beaker with the solution, not touching the bottom of the beaker. The solution was heated and stirred till the solution dissolved.
Acid and base balance of body is normally strongly controlled, keeping the arterial blood pH between 7.38 and 7.42. Acid and base is also important in human homeostasis regarding the appropriate balance between acids and bases; this is also called pH. The body is very sensitive to its pH level, so strong mechanisms exist to maintain it. When pH is imbalanced the protein become denatured and digested, enzymes lose their ability to function, and can cause death. Metabolic Acidosis and Alkalosis: Metabolic Acidosis and Alkalosis are caused by an imbalance of acids or bases and their excretion by the kidneys. Metabolic acidosis produces when the amount of acid in the body is increased through absorption of a substance that can be broken down to an acid.
The equation of the reaction between sodium hydroxide and ethanoic acid is as follows: CH3COOH + NaOH → CH3COONa + H2O We can measure the end point of titration process and we can also measure the amount of reactants. The concentration of ethanoic acid in the vinegar can be determined through stoichiometric calculations, Using the values obtained from the titration, and also the chemical equation as a reference. Phenolphthalein indicator is used in this acid-base titration Equipment and materials:
The soda water will be stored in 5 different temperatures : 5℃, 15℃, 25℃, 35℃, and 45. The desired temperatures will be achieved by using the water bath and refrigerator. I chose phenolphthalein as the indicator, because it is commonly used for titration and is a weak acid. Phenolphthalein is usually used when the solution is strong base and weak acid. When it is added into an acidic solution, the solution will be colourless; when it is added into an alkaline solution, the solution will turn pink.
That caused a new initial reading of NaOH on the burette (see Table1 & 2). The drops were caused because the burette was not tightened enough at the bottom to avoid it from being hard to release the basic solution for titrating the acid. The volume of the acid used for each titration was 25ml. The volume of the solution was then calculated by subtracting the initial volume from the final volume. We then calculated the average volume at each temperature.
CLAIRE MUNTING 29/01/2018 Criterion C EFFECTS OF SURFACE AREA OF CALCIUM CARBONATE UPON RATE OF REACTION Calcium Carbonate Chips 1 Introduction: Within the current investigation, the effects of the surface area of Calcium Carbonate (CaCO3) in combination with Hydrochloric acid (HCl) upon its rate of reaction. CaCO3, commonly referred to as limestone, is an organic substance and is, in a sense, the crystallised “carbonic salt” of the element, calcium2. In addition to being a salt, the pH level of Calcium Carbonate is 9.91, and it is therefore, a basic substance, due to the fact that it is comprised of a pH level higher than 7, which is neutral3. HCl, however, is the bodily acid found in the stomach of human beings.
Weak acid like acetic acid, which do not dissociate with pH value, penerates the taste cells and can also evoke the electrical response. In this mechanism, H+ ion inhibits the potassium channels, which function in the hyperpolarization of the cells. This combination of intake of H+ ion which depolarize the cells and the inhibation of hyperpolarizing channel, together leads to polarization of membrane. The acidic stimuli activates the receptors, which cause decrease in pH and release of transmitters, this cause the excitation of afferent nerve fibers to cortex, which helps in the sour taste sensation.