Chemistry Made Easy

 Hello fam! Today we would be looking at the water of crystallization of a salt. It is common to refer to some salts as hydrates. A hydrate is a salt that has its water of crystallization attached to its structure. The term water of crystallization refers to the number of water molecules that combine chemically, in definite molecular proportion with a salt to form a crystalline structure. The number of water molecules attached to the crystal lattice of the salt is usually written alongside the chemical formula of the salt by placing a dot in between the usual formula of the salt and the number of molecules of water attached to the salt lattice. Examples of salts having water of crystallization are; • Na2CO3.10H2O – Sodium carbonate decahydrate • CuSO4.5H2O  - Copper sulfate pentahydrate • CaSO4.2H2O – Calcium sulfate dihydrate  It is important to note that the presence or absence of the water of crystallization affects the properties of the salt. For instance, CuSO4.5H2O is blue in col

 Yesterday we discussed the uses of salts and today, I want us to discuss what happens when we dissolve a salt in water. In order to keep things as simple as possible, I want to say that when we dissolve a salt in water, the salt is interacting with the water in a unique way. We can say that the salt is reacting with the water.  When a substance is reacting with water, we say that the substance is undergoing hydrolysis. As such, the reaction of a salt with water is called hydrolysis of the salt. The nature of the solution that is formed when a salt is dissolved in water depends on the way the salt is hydrolyzed in solution. Generally speaking; - When a salt is formed from a strong acid and a strong base, the salt solution is neutral. - When a salt is formed from a strong acid and weak base, the salt solution is acidic - When a salt is formed from a weak acid and a strong base, the salt solution is basic. Let us now see the hydrolysis of a few salts to substantiate our argument;  - Cons

 Today, our focus would be on the preparation of salts. We are concerned about how we can make salts. I want to remind you again that a salt is made when hydrogen ion in an acid is replaced by another cation. Let us now consider some of ways by which salts can be made; 1) Reaction of a dilute acid and metal; A salt can be formed when a single replacement reaction occurs between a dilute acid and a metal. The metal used here must be above hydrogen in the activity series. For example; Zn(s) + 2HCl(aq) --> ZnCl2(aq) + H2(g) This kind of reaction is most times given as one of the chemical properties of acids. 2) Neutralization reaction: As I have explained previously, a neutralization reaction occurs between an acid and a base to form a salt and water only. This is one of the most important ways by which soluble salts are formed. For example; KOH(aq) + HCl(aq) -> KCl(aq) + H2O(l) H2SO4(aq) + CuO(s) -> CuSO4(aq) + H2O(l) 3) Dilute acid and carbonate: One of the chemical properties

 Hello, I am glad to be with you again today as we continue to look at the topic, “Salts” in chemistry. Yesterday, we recapped the highlights of our study on complex salts and their different uses. Today we shall look into the broader picture and discuss the uses of salts generally. The different uses of salts are as follows; 1) Salts are used to lower the melting point of ice: It is common during winter to see ice all over the streets making vehicular traffic on the roads quite difficult. In such cases, it is not uncommon to see ice sprinkled on the road in order to lower the melting point of ice and clear the snow off the road. The property applied here is the ability of impurities (in this case salt particles) to lower the melting point of a pure substance (in this case ice). NaCl and CaCl2 are commonly used for this purpose. 2) Salts are used in the process of salting out: I have earlier discussed the process of saponification. In this process, sodium hydroxide is added to fat/oil

 In the past two days, we have been looking at the concept of complex salts and I want us to tie it up today so that we can look at other topics also. I will recap the highlights of our discussion to make it easier for you to remember the key points that we have mentioned in the last two days. I told you that a complex salt contains a complex cation or complex anion or both. The complex cation or anion does have a coordination sphere in which ligands which may be anionic or neutral are bonded to a central metal atom/ion covalently. This is called the coordination sphere of the complex ion.  The number of ligands found in the coordination sphere is the coordination number of the central atom/ion. The complex ion often have ions that balance the charges and these are called counter ions and are located outside the coordination sphere of the complex ion. The bonding between the complex ion and the counter ions is entirely ionic in nature. The geometry of the complex ions depend on the num

 Hello! yesterday, we started looking at the complex salt which we called tetramine copper II chloride with the formula; [Cu(NH3)4]Cl2. We did say that this is a complex salt because of the presence to the complex cation [Cu(NH3)4]^2+. I want to state that if we had a complex anion, the salt would also be a complex salt. A typical example of this is; K4 [Fe(CN)6]. The complex ion is  [Fe(CN)6]4- which is anionic and the counter ions in this case are potassium cations. I told you that we will look at the bonding in the complex salt [Cu(NH3)4]Cl2 and why it does not produce simple ions in water. I will try to explain the basics of the concept today as we would still look at coordination chemistry in more detail sometime later.  Now, the complex salt [Cu(NH3)4]Cl2 has both ionic and covalent bonds. The four ammonia molecules are attached to the central copper II ion by a coordinate covalent bond(see the page timeline for an explanation of what a coordinate covalent bond is). We showed the

 Hello fam! Welcome to today’s lesson. We would focus our study today on trying to understand what we mean by a complex salt. I advise that you look at the lessons on June 18 and July 6, 2023 found on the page timeline for a detailed explanation of the idea of the coordinate bond. I will try to give a little introduction here but looking at the lessons I quoted above are indispensable to making the most out of this lesson.  A coordinate bond is formed when ONLY ONE of the bonding species supply the electron pair that is shared in the covalent bond. In other words, a coordinate bond must involve a  Lewis acid (electron pair acceptor) and a Lewis base, (electron pair donor). Let us look at a typical example. Consider the formation of [Cu(NH3)4]Cl2. Remember that the ground state electron configuration of the copper II ion is written as; [Ar]3d9 4s0.  This implies that we have empty 4s and 4p orbitals that can participate in dsp2 hybridization (forming a square planar complex) along with

 Hello fam! Welcome to today’s lesson. We would focus our study today on trying to understand what a double salt is. While growing up in Nigeria, we had this substance that was used to wash snail before it is cooked. The substance was called “alum”. The substance was used to remove the snail slime so that the snail could easily be prepared in the pot. This same alum was used sometimes for water purification. I remember a number of times that my mother would fetch water from untrustworthy sources due to scarcity of portable water in some parts of Nigeria and she would add this substance to coagulate the particles in the water and cause them to flocculate and subsequently be filtered out.  My mother was a practicing chemist without even knowing it! It was years latter when I gained admission into the University of Nigeria Nsukka and started studying about water purification as a student whose major was Chemistry that I understood what my mother was doing back then when I was a child. Tha

 Hello fam! Welcome to today’s lesson. I am glad to be your host again as we learn chemistry together. Yesterday, we explained the meaning of the term “salt” and I believe that everyone got what we were tying to explain. Today we would start looking at the types of salts. We would continue with this tomorrow but today we are going to look at three kinds of salts for a start.  On a lighter note, I believe our lesson yesterday cleared up the erroneous idea that the only kind of salt that exists is the kind of salt that is used to cook in the kitchen. That one is just sodium chloride enriched with other ingredients to improve our health. We commonly refer to it as table salt. So lets go down to business. What are the types of salts? 1) Normal salts: These are salts that do not contain hydrogen or hydroxide ions in the salt formula. They are usually formed when a neutralization reaction occurs between a strong acid and a strong base such that the reaction is COMPLETE. An incomplete reactio

 Yesterday, we concluded a rich discussion on the pH scale and we solved nine mathematical problems that relate to pH, pOH, pKb, pKa etc then I gave you one problem to figure out on your own. I am still waiting for your response to that self test question.  Just as I announced yesterday, we are beginning a discussion of the concept of salts today. I twice mentioned when we were looking at the properties of acids and bases that formation of salts is a chemical property of both acids and bases. In fact, a salt is formed BY THE REPLACEMENT OF THE HYDROGEN IONS IN AN ACID BY METALS IONS OR OTHER POSITIVELY CHARGED SPECIES SUCH AS AMMONIUM IONS. The preceding phrase was written in upper case for emphasis. My concern in today’s lesson is to explain this phrase so that we can all be on the same page as we proceed in this discussion. I would list five salts and their corresponding acids and see if you can agree with the preceding paragraph after looking at the list; Salt name               Sal

 Hello! I heartily welcome you all to today’s lesson. We are going to look at the last two calculations that pertain to pH, acids and bases today and tomorrow we would commence our discussion on salts to pave way for a discussion on buffers. I hope all the topics so far are making sense? Your feedback would be highly appreciated. Example 8; What is the pH of 0.2 M solution of sodium acetate. The pKa of acetic acid is 1.8 * 10^-5. Solution; We have that the hydrolysis of sodium acetate occurs as follows; CH3CH2COONa(aq) <-> CH3CH2COO^-(aq) + Na^+(aq)    CH3CH2COO^-(aq) + H2O(l) <-> CH3CH2COOH + OH^-(aq) We can see that that the acetate ion acted as a base hence it accepted a proton. We would have to obtain the Kb Kb = 1 * 10^-14/Ka Kb = 1 * 10^-14/1.8 * 10^-5 Kb = 5.6 * 10^-10 Setting up the ICE TABLE, we have that;          CH3CH2COO^-(aq) + H2O(l) <-> CH3CH2COOH + OH^-(aq) I            0.2                                                      0                       

 Hello dear! Welcome to today’s lesson. Do not hesitate to reach out to us via Whatsapp, Messenger or comments on the page if you need clarification on any of the problems that have been solved here. Today, we would continue as usual with mathematical examples on pH and we would be done with all these tomorrow. On Saturday, we shall begin to discuss about salts which would ultimately culminate in a discussion about  indicators as well as the concept of buffers. Stay tuned as we take this long ride! Note; If the ICE tables are not displaying correctly on your device, consider flipping the device to landscape or using another device having a larger screen. Example 6; The pKb of pyridine is 8.77. What is the pH of a 0.010 M aqueous solution of  pyidine. Solution; We  must recall that pyridine is a weak base so the use of an ICE table is indispensable when we try obtain the equilibrium concentrations that would go into the equilibrium equation. We have to set up the ICE table as follows;  

 Hello fam! Welcome to today’s class, we are continuing along the path that we started a few days ago. We have been looking at different problems that have to do with the pH and today we shall look at some more problems. Example 3; A solution has a pOH of 6.50 at 50oC. What is the pH of the solution? Solution; We know that; pH + pOH = 14 pH = 14 – 6.50 pH = 7.5 Example 4; Calculate the pH and pOH of 0.02 M H2SO4. Solution; We know that we would first find pH because it is an acid; pH = -log(0.02 M) pH = 1.69 pOH = 14 – 1.69 =12.31 Example 5; Calculate the pH and pOH of a solution of 3 * 10^-2 M Solution; We know that we would first find pOH because it is an base; pOH = -log(3 * 10^-2) = 1.5 pH = 14 – 1.5 = 12.5

 Hello fam! You must have noticed that there was no lesson updated on our page yesterday. This is due to the fact that I have been ill since the weekend and I am currently taking as much rest as possible. I am recovering gradually. I was advised to take out the whole of yesterday to rest hence I was of duty and couldn’t deliver the lesson for yesterday.  Like I said in on Sunday, we shall look at mathematical examples of pH, pOH, pKa and pKb. Let’s get started with two examples today. Example 1; Find the pH of 0.0025 M HCl solution Solution; The first thing that must come to our mind is that HCl is a strong acid hence it completely dissociates in water. Since it dissociates completely, we do not need an ICE table in order to determine the pH. The ICE table would otherwise be necessary when we are dealing with a weak acid. We now use the formula; pH = -log[H^+] Where we have; [HCl] = [H^+] = [Cl^-] =  0.0025 M  pH = -log(0.0025 M) pH = 2.6 Example 2; What is the hydrogen ion concentrati

 Hello, yesterday, we started off looking at the meaning of the term pH in chemistry and we agreed that the pH is defined as the negative logarithm of the hydrogen ion concentration. In modern chemistry, the p stands for "the negative decimal(base ten) logarithm of". Previously we saw that pKa means the negative logarithm of the acid dissociation constant. Also, pKb means the negative logarithm of the base dissociation constant. Do you now see that our definition of the term “p” in chemistry holds true always? Closely related to the pH is another term called the pOH. The pOH is the negative logarithm of the hydroxide ion concentration. Thus, while pH and pKa applies to acids, pOH and pKb applies to bases. Is that making sense? Without much ado, we have to bear in mind that the pH tells us how acidic a substance is. It is the indicator of the degree of acidity or alkalinity (basicity) of a substance. Generally, the pH of substances can be arranged in a scale of 1 – 14 and this

 Hello, In today’s lesson, we would discuss about a term that has come up once before in our discussion and I promised to delve into more details about it at a latter time.  Hence, we are going to look at the meaning of the term pH. In our lesson today, we would try to understand the meaning of pH. The term "pH" was first described by Danish biochemist Søren Peter Lauritz Sørensen in 1909. pH is an abbreviation for "power of hydrogen" where "p" is short for the German word for power, potenz and H is the element symbol for hydrogen. The H is capitalized because it is standard to capitalize element symbols. The abbreviation also works in French, with “pouvoir hydrogen” translating as "the power of hydrogen.” In today’s language, we understand the pH to be the negative logarithm of hydrogen ion concentration. That is; pH = -log(H^+) Or pH = -log(H3O^+) In tomorrow’s lesson, we shall try to understand the pH scale and how the scale works. See you then! Ho

 Hello! Welcome to today’s lesson. It’s indeed very awesome that we have made this much progress learning together as an online community. We look forward to doing greater things together. As we explained yesterday, today we would look at more uses of bases and you would certainly find this very interesting. Yesterday, we saw the important role that bases play in the body when the acidity in the stomach goes above the normal level. It would interest you to know that in petroleum refining, an important step is to wash the raw crude with strong acids such as oleum. This serves the purpose of removing impurities in the crude. If we charge this highly acidified crude into the refining tower, the acid in the crude could corrode the metal used to make the tower and badly damage it. Hence an equally strong base such as NaOH is used to wash the crude oil so that the acid is neutralized before charging the crude oil into the refining tower. All of you use soap right? Let me tell you how soap is

 It is common knowledge that digestion commences at the mouth and ends in the small intestine. We know that digestion of food is the major way that animals are able to access the nutrients that are necessary for life. The stomach is a very important part of the body that takes part in digestion. However, the stomach is quite acidic.  The acidity of the stomach results from the production of gastric acid in the stomach. Gastric acid is produced when a hormone called gastrin gives a signal to the parietal cells in the stomach. The function of the gastric acid is to minimize the growth of microorganism in the stomach and also kill any microorganisms that may have been ingested alongside food substances.  Secondly, gastric acid is involved in the activation of pepsinogen to give pepsin which is an important step in the digestion of proteins. Thirdly, the gastric acid generally assists the breakdown of food particles in the stomach so as to aid easy digestion of food particles. The body has

 Hello fam, I believe that we are really getting somewhere as we study together all these while. Chemistry Made Easy is a large learning community that is growing by leaps and bounds. I am glad to announce that our YouTube channel would be fully functional by August 1. We would also have a live seminar about how to study chemistry and understand it better on this platform before the end of July(the date would be communicated in due course). To join our WhatsApp group, kindly send a Whatsapp message to +234 809 052 6258 . Today we would be discussing about the properties of bases. We shall divide the properties of bases into physical properties and chemical properties. Physical properties of bases; 1) A caustic base is corrosive: This implies that a concentrated base solution could burn off your skin and destructively interact with other surfaces. Caustic potassium hydroxide or sodium hydroxide are important examples of caustic bases. For the definition of a concentrated solution, check

 When we discussed about acids, I explained that the extent to which an acid is dissociated in solution is shown by the acid dissociation constant. Then I went ahead to explain that the percent dissociation of the acid can be obtained by the formula; α = √Ka/C * 100/1 Where  α = percent dissociation Ka = acid dissociation constant C = concentration. Refer to the post on June 22, 2023 found on the page timeline for more details on this. Now, for a base we have the percent dissociation as; α = √Kb/C * 100/1 The only new term here is Kb which we have described as the base dissociation constant. Example 3; Calculate the percent dissociation of a 0.6M aniline solution if the Kb for aniline is 3.8 * 10^-10. Solution; From the parameters in the question; Kb = 3.8 * 10^-10 C = 0.6 M Substituting the parameters into the formula given above; α = √3.8 * 10^-10/0.6 * 100/1 = 0.0025% Thus the percent dissociation of 0.6 M aniline is 0.0025%. I believe that the solution to this problem is clear. I w

 Hello, we are here again to continue from where we left off yesterday. Yesterday, we solved a mathematical example that helped us consolidate on the ideas that we have discussed about the base dissociation constant Kb. Today I would solve another example and then give you one to try out on your own. You can drop your answer to the self test question as a comment under this post. Example 2; Calculate the concentration of the hydroxide ion in a 0.1 M solution of hydrazine if the pKa of the solution is 7.95. Solution; We are told to obtain the concentration of the hydroxide ion that is contained in a given concentration of hydrazine solution. We must first write down the reaction equation as follows; N2H4(aq) + H2O(l) ->N2H5^+(aq) + OH^-(aq) We can see that what we have here is the value of the pKa thus we must find a way to obtain the pKb because hydrazine is not an acid but a base(because it accepted a proton in this reaction). Some days ago I introduced the idea of the ion product