Investigating the Effect that Concentration Has on a Reaction
INTRODUCTION
============
Aim- to investigate the effect that concentration has on a reaction on
these factors:
* Temperature rise
* Heat evolved
* Heat given off due to the neutralization between Hydrochloric Acid
and Sodium hydroxide solution.
Neutralization takes place when acids react with substances called
bases. When they react their acidity is cancelled out, and the
reaction always produces a salt and water. The base can be soluble
(when called an alkali) or insoluble like copper (II) oxide.
Neutralization can be used for:
* Treating insect bites (that are acidic)
* Making fertilizers and other salts in industry.
* Reducing the acidity in soil, to make it better for plants to grow
and live in it.
The heat of neutralization is the heat change when 1 mole of the acid
used is neutralized. That is, it is the heat given out when water
molecules are produced from one mole of acid.
Following is the ionic equation that is stated for the neutralization
reaction that we will carry out in the lab.
NaOH(aq) + HCL(aq) --―> NaCL(aq) +H2O(l)
[IMAGE]
[IMAGE]
[IMAGE]
[IMAGE]
Na+ + OH- + H+ + CL- --―> Na+ + CL- + H2O
H+(aq) + OH-(aq) --―> H2O(l)
Hence, Na+(aq) + CL-(aq) --―> NaCL(s)
-------------------------------------
When the hydrochloric acid is mixed into the sodium hydroxide
solution, the ions react with the various other ions present in the
solution.
In this increased (in volume) solution, the spectator ions are Na+ and
CL-, as the ions of H+ and OH- react to form H2O. These spectator ions
(Na+ and CL-) do not react to form a salt until the Water is formed
from the H+ and OH- ions.
In this reaction all four ions present, form bonds between each other,
Baking Soda and Vinegar: Limiting Reactant Lab Background The limiting reactant of a chemical reaction is the substance that places an upper bound on the amount of product that the reaction can produce. The limiting reactant places this upper bound because the reaction must stop once all of the limiting reactant is consumed. If the relative amount of reactants is altered, then the limiting reactant may change accordingly.
Afterwards, we conducted crystallization to evaporate the liquid in an attempt to detect the presence of a salt. Before stating which of the potential
have either not stir the mixture or use a machine to stir it at the
Common salt is necessary in everyday lives because it carries vital substances. It also has many uses, but is found to be used in food only one percent of the time (McGrath and Travers, 1999). It is used to clear ice and snow off of roads, during the production of chlorine, in livestock feeding, to preserve foods, and to improve the taste of some foods. (Aasen, et Al 1999).
Investigating the Effect of Concentration on the Rate of Diffusion Aim: To find out if concentration affects the rate of diffusion. Prediction: I predict that the higher the concentration of acid the faster the reaction will be. Hypothesis: Diffusion is the spreading out of a gas or liquid from an area of low concentration to another area where it has a lower concentration until the overall concentrations are balanced. The Hydrochloric acid (HCl) diffuses into the gelatine cube of which contains Sodium Hydroxide (NaOH), which is an alkali. When the Hydrochloric acid combines with the Sodium Hydroxide they form salt and water, which is neutral therefore turning the pink cube to clear.
Cations are positively charged ions, which are attracted to their negatively charged counterparts, anions. Precipitates can form when these cations and anions combine in aqueous solutions; however, precipitates only form if one of the products of the chemical reaction is not soluble in that solution. Solubility is instrumental in understanding how precipitation reactions occur. This is because solubility rules, determine whether a precipitate can form. A precipitate can form if the cation in the compound is soluble when combined with an anion. For example when the solutions silver nitrate and sodium chloride (reactants) are mixed, silver chloride and sodium nitrate (products) are formed. Following the solubility laws, silver nitrate is the precipitate, as it isn’t
CaCl2 + H2O + CO2
Lewis acidic because it is able to donate a hydrogen ion (Kotz et al., 1996).
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).
carbonate and hydrochloric acid,. I will look at the various factors. affecting the reaction and select one variable to change, while the others keep constant in order to carry out a detailed investigation. Formulae = ==
The Effects of Concentration on Reaction Rate with Sodium Thiosulphate ---------------------------------------------------------------------- Planning = == == =
When evaluating the results from Investigations 1 and 2, it can be seen that the most influencing factor on the percentage of diffusion was the different surface area of the agar. As predicted in the second hypothesis, the 1cm cube had the highest diffusion percentage with 21.6% of the cube being affected in 8 minutes. This is a significant difference of 18.17% when compared to the 2cm cube’s diffusion percentage of 3.43 and a 20.38% difference from the 2.5cm cube’s result of 1.22%. Investigation 1’s results show that the most successful concentration of acid to diffuse through the phenolphthalein was the 1M with a percentage of 1.81. This is a 0.47% difference from the results of the 2M sulfuric acid. Graph 2 demonstrates that the diffusion percentage continued to incline when the concentration increased however starts to decrease past the 1.8 point. These results were unexpected and so a fifth trial was run in order
Cl- (aq) + Na+ (aq) + OH- (aq) Na+ (aq) + Cl- (aq) +H+ + OH- [IMAGE]The above is an example of a neutralization reaction, involving an acid and an alkali. The result is a salt and water. In every neutralization reaction, the metal in the alkali (Na+ here) takes the place oh the hydrogen in the acid, forming a metal compound called a salt.
to see when the x marked paper is not visible. I repeatedly did this 3
The simplest experiment for this type of situation would be to use red and blue litmus paper to distinguish between acids, bases and salts. Hydrochloric acid (HCl) makes blue litmus paper change color going from blue to red, making it an acid. Sodium hydroxide (NaOH) makes red litmus paper change color going from red to blue, making it a base. Sodium chloride solution (NaCl) is neutral, since it would only soak blue and red litmus paper, considering that it is a by product of when an acid and a base mix together, neutralizing each other.