module 2.4 inorganic compounds which include water acids bases and salts biochemistry is the term that means the chemistry of life so if you look at the term itself bio is a reference to biology the study of life and chemistry so we're going to look at the chemistry all the chemical reactions which go on to sustain life and we have inorganic compounds definition of an inorganic compound compounds that generally do not contain carbon bonded to hydrogen so our examples of things that are or inorganic compounds include water acids bases and salts they don't contain many carbons bonded to hydrogen whereas organic compounds are those substances that do contain a lot of carbon bonded to hydrogen so you see here a hydrocarbon chain this would be we'd have lots of these in a fatty acid lots of carbons to hydrogen that makes it organic or here with our hydrocarbon ring a ring of carbons with hydrogens bonded to it that makes it organic if you think about water h2o there is no carbon in there hydrogens hydrochloric acid or bases ammonia there are no carbons in those products we are going to in this chapter focus on the inorganic compounds we're going to leave the organic compounds and discuss those when we get into physiology the four main organic compounds in the human body include carbohydrates lipids proteins and nucleic acids so let's start our discussion of inorganic compounds with a discussion about water is water any important substance in the human body absolutely it is vital for human life water serves as the body's primary solvent it's often called the universal solvent because so many polar and ionic solutes will dissolve in their entirety or to some degree in water so what type of substances would water dissolve water is only able to dissolve hydrophilic solutes hydro water philic loving what would make a solute water loving any solute with a full or partial charge so the rule is like dissolves like water will dissolve any ionic or polar covalent solute so the example that they give down here is sodium chloride and ionic substance so sodium chloride is basic table salt and we all know that if you took table salt put it into a glass of water and stirred it would it dissolve of course it would it would make salt water so why does sodium chloride get along with water remember how water is polar covalent it's got its partially negative and partially charged uh positive hydrogens so when we put sodium chloride into water the oxygen molecules with their negative charge start snuggling up to the sodiums and the hydrogens with their positive charges start snuggling up to the chloride and pretty soon it breaks the ionic bond which keeps the sodium and the chloride together so they have ionized and they are now in solution water has dissolved sodium chloride here's an example of a polar covalent compound that will dissolve in water now this compound is carbon monoxide that substance that can make us sick if we breathe too much of it from a house fire or from exhaust fumes so carbon monoxide is a relationship between carbon and oxygen and in this case the electronegativity of oxygen is greater than the electronegativity of carbon so oxygen keeps the electrons for a greater share of the time than carbon giving the oxygen a negative charge and the carbon a partially positive charge will water get along with this molecule that has partial negative and positive charges yes it will the hydrogens associate with the oxygen end and the oxygen associates with the carbon end solutes that do not have full or partially charged ends are called hydrophobic water fearing they do not dissolve in water and these include uncharged polar covalent molecules such as oils and fats so if you pour olive oil into water what would it do it would float on top and that's what they're trying to show you here in this case they use methane they're not using olive oil but methane it's got similar nonpolar covalent bonds and why do these two not interact with each other because water has partial positive and negative charges there is no partial negative or positive charge on methane so there's no way for these two compounds to interact with each other therefore this is an example of a hydrophobic compound okay now let's switch our subject from water to acids and bases another type of inorganic compound so the study of acids and bases is really the study of the hydrogen ion so make sure you've got that down what is a hydrogen ion it is a proton that's really all it is so two definitions an acid is a hydrogen ion donor so an acid can give up a hydrogen ion what are examples hydrochloric acid when you put it into water will ionize into a hydrogen ion and a chloride ion another example is carbonic acid when you put carbonic acid into solution some of it will ionize into a hydrogen ion and a bicarbonate ion so an acid can donate a hydrogen ion what is the base it's the opposite of an acid so a base is a hydrogen ion acceptor examples include sodium hydroxide so when you put sodium hydroxide into water you get a sodium ion and a hydroxyl ion would this hydroxyl be able to accept a hydrogen yes it would because the negative would attract the positive and it would basically neutralize or accept the hydrogen second example is sodium bicarbonate when you put this into solution some of it will ionize into a sodium ion and a bicarbonate ion would this accept a hydrogen with its positive charge yes it would that would then become carbonic acid this slide visually shows you what happens when you add an acid into water it will ionize and your definition of an acid is anything that generates hydrogen ions so you put the hydrochloric acid into water and it generates hydrogen ions just like an acid should what's the definition of a base here we have sodium bicarbonate put it into water it ionizes so the sodium separates from the bicarbonate and the definition of a base is anything that accepts a hydrogen and you see that happening here in this image so the ph scale is actually pretty simple it ranges from 0 to 14. it is a simple way of representing hydrogen ion concentration of a solution so many students don't recognize how simple this really is when i say what is the ph scale it is simply a measure of the number of hydrogen ions in solution that's really all it is each single digit change in the ph number equals a 10 fold change in the hydrogen ion concentration so let's take a look at an example how much of a change in hydrogen ion concentration occurs if the ph goes from seven to five so the first thing you need to think about is when you go from seven to 6 that's a 10-fold change because each single digit represents a 10-fold change so between 7 and 6 we have a 10-fold change and between 6 and 5 we have a 10-fold change you don't add those together you multiply them together so when you go from 7 to 5 it's 10 times 10 or 100 times more hydrogen ions at the ph of 5 than at the ph of 7. what if we go the opposite direction what if we go from a ph of seven to ten so in this case there's a ten-fold change from seven to eight a ten-fold change from eight to nine and a ten-fold change from nine to 10. so 10 times 10 times 10 means that at a ph of 10 we have a thousand times less hydrogen ions than we have at a ph of 7. that nature is called the logarithmic nature of the ph scale all right this one will be fairly easy to explain here on the right we have our ph scale going from 0 to 14. right in the middle is seven what does seven represent seven represents a solution that is neutral what does that mean it has equal numbers of base and hydrogen ions so they balance each other out any ph that is less than seven has more hydrogen ions than base ions so we call that a solution that is acidic and any solution with a ph greater than seven has more base ions than it has hydrogen ions so it makes it basic or alkaline blood ph must remain within its narrow range to maintain homeostasis so ph is one of those variables that we have to maintain within a fairly narrow range what is that range 7.35 to 7.45 that is the average ph of blood when it is in homeostasis and that makes blood slightly basic just a little bit basic so in order to maintain this narrow ph range we have to have mechanisms in the human body that help to keep it there a buffer is one of those mechanisms so the definition of a buffer is a chemical system that resists changes in ph and we will be covering half of a chapter at the end of physiology which talks about how the human body maintains ph there are actually three systems in the human body that maintain ph the first is our chemical buffer systems that resist changes in ph immediately the second system is the respiratory system and it contributes by maintaining proper levels of carbon dioxide in the human body and third is the renal system and the renal system contributes to ph by excreting excess hydrogen ions or bicarbonate ions depending upon the state of the body so the last inorganic compound that i wanted to touch upon in this module is salts and electrolytes by definition salts can dissolve in water to form cations and anions called electrolytes which are capable of conducting electrical currents so sodium chloride was an example we also have calcium chloride potassium iodide there's numerous salts that the human body consumes what do these electrolytes do for us one thing is that electrolytes are responsible for helping with the generation of nerve impulses so that's an example of an electrical current another thing that electrolytes are absolutely necessary for is muscle contraction so both nerve impulse conduction and muscle contraction are very very dependent upon proper levels of electrolytes electrolytes also attract water if you think about it salts attract water so the other thing that salts are very important for in the human body is helping to maintain the proper fluid balance in the human body review questions for module 2.4 what types of substances dissolve in water polar covalent in ionic substances dissolve well in water explain why these substances dissolve in water water acts as the universal solvent with any substance that has partial or whole charges so ionic compounds have hole charges and polar covalent molecules have partial charges what doesn't dissolve well in water any substance such as oil which is dominated by nonpolar covalent bonds number two hydrophobic means water fearing hydrophilic means water loving number three ph is a measure of the number of hydrogen ions in solution number four a ph of 3 is considered acidic and a ph of 9 is considered alkaline number five what is a buffer the definition of a buffer is any chemical that helps to resist large swings of ph in the human body and number six what is the normal ph of blood plasma the normal ph of our blood plasma ranges from 7.35 to 7.45