Exercise 1: Calculating The Mean
The sample mean is the average value for a finite set of replicatemeasurements on a sample. It provides an estimate of the population mean for the sample using the specific measurement method. The sample mean, denoted , is calculated using the formula:
Suppose we use atomic absorbance spectroscopy to measure the total sodium content a can of soup; we perform themeasurement on five separate portions of the soup, obtainingthe results 108.6, 104.2, 96.1, 99.6, and 102.2 mg. What isthe mean value for the sodium content of the can of soup?
You have already used the relevant Excel functionsfor this calculation in . Set up a new worksheet and calculatethe mean value, using the COUNT and SUM functions, and the AVERAGEfunction; you should get the same values.
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Calculating Standard Reduction Potential For Zinc Electrode
We are describing here a method of calculating standard reduction potential by taking a zinc electrode in half cell with zinc sulfate against standard hydrogen electrode. Standard reduction potential and standard oxidation potential for standard hydrogen potential is always taken 0.00. Experiment is described below-
Construction of standard hydrogen electrode – To construct standard hydrogen electrode, we take a hydrogen chloride solution of 1M in a glass beaker. Now a platinum inert electrode with platinum black foil at one end is immersed in the beaker and a glass jacket is kept on it to prevent entry of oxygen. It has an inlet for pure hydrogen gas to enter in the solution. Temperature is maintained at 25. A figure of Standard Hydrogen Electrode is shown below-
This half cell of standard hydrogen electrode is connected with half cell of zinc electrode. For this, zinc sulfate is taken in a beaker and a zinc rod is dipped in it. 1M concentration of electrolyte zinc sulfate is taken. Temperature is maintained at 25. Now this zinc electrode is connected to a standard hydrogen electrode by using a voltmeter. Which will measure electrode potential of the cell. Salt bridge is also used which prevents intermixing of the solutions and maintains electrical neutrality of the solutions. Zinc half cell is taken as cathode and hydrogen half cell is taken as anode.;
E0cell = E0cathode E0anode
;;;;;;;;;;;; E0cell = E0Zn2+/Zn E0H+/H2 ————–
E0cell = E0cathode E0anode
E0cell = +0.34
What Is Electrode Potential
According to IUPAC electrode potential has been defined as follows-
In electrochemistry the electrode potential is the electromotive force of a cell built of two electrodes.;
It is denoted by the sign E. It is not possible to measure accurately the absolute value of single electrode potential directly. Only the difference in potential between two electrodes can be measured experimentally. So, in an experiment to measure electrode potential, in a cell one electrode is used as a reference electrode whose potential is already known and another electrode is used of unknown potential. Cell potential is measured experimentally which is equal to the sum of potentials on the two electrodes.
ECell = ECathode + EAnode
Ecell is measured by voltameter experimentally and electrode potential of one electrode is already known so electrode potential of another can be calculated.
What Does Standards Mean In Education
Educational standards are the learning goals for what students should know and be able to do at each grade level. Education standards, like Common Core are not a curriculum. In other words, the Common Core is what students need to know and be able to do, and curriculum is how students will learn it.
What Is The Importance Of Standardization In Chemistry
The so-called titer determination or standardization of a volumetric solution used for titration is one of the most important preconditions for reliable and transparent titration results. Accurate and reliable titration results are only achievable when we work with the exact concentration of the volumetric solution.
Examples Of Standardize In A Sentence
standardizedstandardizestandardize Forbesstandardize BostonGlobe.comstandardize STATstandardize Wiredstandardize Fox Newsstandardize Anchorage Daily Newsstandardize BostonGlobe.comstandardize ProPublica
These example sentences are selected automatically from various online news sources to reflect current usage of the word ‘standardize.’ Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
What Is Standardization Of Naoh And Why Is It Important
Standardization is the process of determining the exact concentration of a solution. In the second procedure the standardized NaOH will be used to determine the molarity of a hydrochloric solution .
Subsequently, question is, why is NaOH used in titration? It is a strong alkaline reagent and produces a sharp change in pH which makes titration easier to do.
In this way, why is standardization important in titration?
The so-called titer determination or standardization of a volumetric solution used for titration is one of the most important preconditions for reliable and transparent titration results. The nominal concentration of a volumetric solution used as a titrant in the titration process is known.
Why do you need to standardize the acid and or base?
Standardization is the process of determining the exact concentration of a solution. Titration is one type of analytical procedure often used in standardization. In a titration, an exact volume of one substance is reacted with a known amount of another substance.
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What To Consider When Standardizing Titrant
If you perform titrations on a regular basis, then youve certainly heard about standardization of the titrant. When carrying out a standardization you determine the titer, which is a correction factor for your titrant concentration, as it is normally not exactly the value written on the reagent bottle label. In this blog entry, I want to give you some valuable information about why standardization is important and how to determine the titer.
Please note this blog entry will not deal with the standardization of Karl Fischer titrants.
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What is the titer factor?
Titration is an absolute method , meaning it is of utmost importance to know the exact concentration of the titrant you are using for your results to be accurate and repeatable by other analysts. This is why you need to carry out a standardization.
Usually the difference between the nominal concentration and the absolute concentration is given by a dimensionless factor . The absolute concentration is obtained by multiplying the nominal concentration with this factor, which is usually called «titer». In some cases, it is the absolute concentration which is called «titer».
Why should you standardize your titrant?
What can I do to prevent changes to the titer factor?
Titrants best stored in brown glass bottles:
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Limitation Of Standard Electrode Potentials
Standard electrode potentials can be applied to aqueous equilibrium only. We can predict reaction possibilities, but we cant predict rate of reaction by using standard electrode potentials.;
This was a brief on standard electrode potential, if you are looking for detailed study notes on various topics of electrochemistry then register yourself on Vedantu or download Vedantu learning app.;
Definition Of Standard Addition
Standard addition is used in quantitative analysis of chemicals.It is a calibration method that involves adding an additional amount of the substance of interest to a sample when a one-off or infrequently performed analysis is required.
An analyst usually divides the unknown sample into two portions, so that a known amount of the analyte can be added to one portion.These two samples, the original and the original plus spike, are then analyzed.The sample with the spike will show a larger analytical response than the original sample due to the additional amount of analyte added to it.
The difference in analytical response between the spiked and unspiked samples is due to the amount of analyte in the spike.This provides a calibration point to determine the analyte concentration in the original sample.
The procedure is suitable when, for example, due to matrix effects the analytical response for an analyte in a complex sample may not be the same as for the analyte in a simple standard.In this case, calibration with a working curve would require standards that closely match the composition of the sample.
For routine analyses it is feasible to prepare or purchase realistic standards, e.g. NIST standard reference materials.For diverse and one-of-a-kind samples, however, this procedure is time consuming and often impossible.
An alternative calibration procedure is the standard addition method as outlined at the beginning of the page.
The F- concentration in the original sample is:
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Main Difference Standardization Vs Titration
Standardization and titration are two related chemical terms. Although they use the same technique to get a measurement, their applications are different from each other. Standardization is used to determine the exact concentration of a prepared solution. Titrations are used to determine the unknown concentrations of samples. Most often, standardization is also done as a titration. The main difference between standardization and titration is that standardization processes essentially uses primary standard solutions whereas titrations do not essentially use primary standard solutions.
Why Do We Standardize Solutions
They should have a relative molecular mass such that a solution of about 0.
01 M to 0. MM can be prepared easily. A standard solution of Noah cannot be made by direct weighing. This is because Noah is hygroscopic and will therefore absorb moisture from the air. Therefore, a standard solution of some stable acid has to be prepared to standardize the given Sodium Hydroxide solution. This can then be used to determine the unknown concentration of the Hydrochloric acid solution.
In the experiment, two titration were therefore performed: Titration A: Standardization of Sodium Hydroxide solution using standard solution of Oxalic acid. Titration B: Determination of the concentration of Hydrochloric acid solution using the standardized Sodium Hydroxide solution. The terms used in titration are therefore used here too. Therefore, in titration A, the analyze was the Sodium Hydroxide solution; and the iterant was the Oxalic acid. In titration B, the analyze was the Hydrochloric acid solution; while the iterant was the Sodium hydroxide solution.
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What Increases Cell Potential
Through increasing the concentration of one of the electrolyte solutions, you increase the number of cations and anions , thus increasing the cells voltage potential.
To learn more about this concept and other concepts related to electrochemistry, register with BYJUS and download the mobile application on your smartphone.
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Standard Electrode Potential Example
The calculation of the standard electrode potential of a zinc electrode with the help of the standard hydrogen electrode is illustrated below.
It can be noted that this potential is measured under standard conditions where the temperature is 298K, the pressure is 1 atm, and the concentration of the electrolytes is 1M.
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Preparation Of Standard Solution Of Sodium Carbonate
A standard solution is a solution whose concentration has been accurately determined. Standard solutions are prepared from highly pure chemicals and the exact concentration is determined by a process called standardization. The substance available for standardization of a solution is highly pure is called a primary standard.
What Is The Difference Between Standardization And Titration
Standardization and titration are important terms we use in analytical chemistry. Standardization is also a titration process, but not all titrations are standardization processes. The key difference between standardization and titration is that standardization process uses primary standards, whereas the titration process does not essentially use primary standards. In standardization, the solution in the burette is the primary or secondary standard solution, while titration contains a standardized solution.
The below infographic summarizes the difference between standardization and titration.
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What Is A Secondary Standard Solution
A secondary standard solution is a solution that is made specifically for a certain analysis. A secondary standard is a substance whose active agent contents have been found by comparison against a primary standard. This means it is usually standardized against a primary standard.
Secondary standard solutions are used to calibrate analytical equipment and analytical techniques. These solutions do not fulfill the requirements of a primary standard. A secondary standard has a less purity than a primary standard. These are less stable and chemically reactive than primary standards. Therefore these compounds can get contaminated.
Figure 2: Potassium permanganate solution is a secondary standard solution.
Anhydrous sodium hydroxide is a secondary standard. It is highly hygroscopic. Potassium permanganate is another compound that is often used as a secondary standard. It is less stable and is reactive. Therefore when a Potassium permanganate solution is being prepared, it has to be standardized with a primary standard.
Why Is Standard Solution Of Naoh Cannot Be Prepared
NaOH is a hygroscopic substance. It absorbs moisture, therefore, it cannot be weighed and that is why its standard solution cannot be prepared directly.
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The Need For A Common Language
Every field of science involves taking measurements, understanding them, and communicating them to others. In other words, we all have to speak the same basic language. Whether you are a chemist, a physicist, a biologist, an engineer, or even a medical doctor, you need a consistent way of communicating size, mass, shape, temperature, time, amount, energy, power, and speed.
Consider the screen on which youre reading this text right now. It might be an LCD screen, which is made up of liquid crystals. The chemist developing a specific formulation for a liquid crystal has to meaningfully communicate information to an engineer so that the engineer knows how to manufacture it. The engineer, in turn has to be able to communicate with other engineers, physicists, and chemists to design the circuit boards, display screens, and electronic interfaces of the rest of the computer. If these people dont all speak the same language, the enterprise will never get off the ground.
The International System of Units is the metric system used in science, industry, and medicine. Depending on your age and geographic location, you might be very familiar with the imperial system, which includes units such as gallons, feet, miles, and pounds. The imperial system is used for everyday measurements in a few places, such as the United States. But in most of the world and in all scientific circles, the SI system is in common use.
Chemistry Scientific Units the SI and Metric Units YouTube
What Is Standard Electrode Potential
The potential of the half-reaction measured against the standard hydrogen electrode under standard conditions is called the standard electrode potential for that half-cell or half reaction. Standard conditions mean temperature at 298K, pressure should be 1atm, concentration of the electrolyte used should be 1M. It is measured with respect to standard hydrogen electrodes.;
Standard hydrogen electrode is a gas ion electrode. It is used as a reference electrode for determination of standard electrode potential of elements and other half cells. It can act as anode half – cell as well as cathode half-cell. Value of its standard reduction potential and standard oxidation potential is always zero at 25 or 298K. It is the base of the thermodynamic scale of oxidation reduction potentials. We have already discussed standard hydrogen electrodes in detail in another article available on Vedantu.;
Standard electrode potential is denoted by E0. Either Standard reduction potential or standard oxidation potential can be calculated for an electrode using standard hydrogen electrode. Standard cell potential is the difference between standard reduction potentials of two half cells or half reactions. It can be represented as
E0cell = E0cathode E0anode
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