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Acid,Base,Buffer
SIUE-Nicole's Flashcards
Question | Answer |
---|---|
Define acid base balance | Concentration of H+ ions. Regulated by the body, and the balance b/t intake (production) & net removal of H+ ions from the body. |
The range on the pH scale is mostly used from 0-14, can the pH go above or below these numbers? | Yes, in both directions. It can go below 0 or above 14. |
The pH scale is the measure of? | The activity of H+ ions in a solution, its acidity or alkalinity. |
In a neutral solution, what equals what? | Hydrogen ions=hydroxide ions |
What is the pH of water? Do we assume this as neutral? | 7, yes we assume water as neutral. |
H3O+ (hydronium) becomes what? | Hydroxide (OH-) |
When water is left out in an open container what happens? | CO2 dissolves in the water and makes it acidic. |
What is the water equilibrium principle? | Assuming that water is neutral, the addition of exponents of H+ & OH- ion concentration always equal the exponent -14. |
What two ions are ALWAYS present in every solution? | H+ and OH- ions. |
If there are excess H+ ions in a solution is it acidic or basic? | Acidic |
If there are excess OH- ions in a solution is it acidic or basic? | Basic |
If the H+ ion exponent is 10, what is the OH- ion exponent? | 4, they have to equal 14. |
What measure the H+ ions in a solution? | pH |
What produces H+ ions? | Acids |
Acid is a pH less than what? | < 7 |
If you were given a pH of 7, what would the H+ ion concentration be? | 0.0000001--> Put 1 over what the pH is and divide. 1/7. |
What is the H+ ion concentration of HCL with a pH of 2? | 0.01--> Put 1 over pH and it is 1/2. |
Is 0.0000001 or 0.01 more acidic and how do you know? | 0.01 is more acidic because it is closer to one. The bigger the #, the more acidic and the more H+ ions are completely dissociated. |
Units of moles of H+ ions per liter of solution is...... | pH |
1 x 10^0 = a pH of? | pH= 0 |
1 x 10^-9= a pH of? | pH= 9 |
Acids have been given different definitions that mean what? | Oil- water-soluble and Sour- sour tasting. |
What happens to the pH when an acid is dissolved in water? | It gives a solution with a pH of less than < 7. H+ ions are given up in the water. |
What does an acid give up to a base? | It gives up a proton (H+) ion |
What can an acid accept from a base? | An unshared pair of electrons from a Base. |
In a neutralization rxn what is formed and what reacts together? | An acid reacting with a base to form a salt in water. |
Acids give up their H+ ions in water and therefor increase what other ion with the bonding of H+ ions? | Hydronium ion (H3O+) concentration is increased in the water. H+ given up by acid and binds with H2O (neutral) to form (H30+) |
What is an ionic compound and give an example of one. | Ionic compound is composed of positively charged cations and negatively charged anions for an overall neutral or no net charge. Salt is an example. |
NH3(base) + HCL(acid)--> NH4Cl(salt) Is this solution neutral, acidic, or basic? | Neutral, a base and an acid form an ionic compound of a salt in which is neutral. |
Define alkaline | Chemical compound that absorbs hydronium ions when dissolved in water. They accept protons (H+) ions. |
What reduces the hydronium ion (H30)concentration in water? | Base--> H30 a base accepts H+ (proton) from H30. |
What is less viscous that pure water and has a bitter taste? | Base |
Feels soapy to the touch? | Base |
When HCL is poured into H2O what happens? | HCl + H2O--> H+ & Cl-. When an acid is poured into water it gives up H+ to the water. |
The more the pH approaches 1, indicates what kind of acid? | Closer to 1 indicates a strong acid. |
When NaOH is poured into H2O what happens? | NaOH + H2O--> Na+ & OH-. When a base is poured into water it gives up OH (hydroxide) to the water. |
The closer to 14 a bases pH is, means it is strong or weak? | Strong |
What happens when H+(acid) & OH-(base) are mixed together? | H20 is formed. pH=7 A salt is also formed. |
HCL (acid) + NaOH (base)--> HBR (acid) + KOH (Base)--> | H2O (water) & NaCl (salt), H2O (water) & KBr (salt) |
What is a conjugate acid and base? | When an acid gives up a proton (H+) and a base accepts the proton (H+), the base that accepted the proton (H+) is now an acid and the acid that gave up its H+ is now the conjugate base of its previous acidic state before its proton (H+) was lost. |
Does every acid have a conjugate base, and does every base have a conjugate acid? | Yes, proton (H+) donor (acid) is now a base, and proton (H+) acceptor (base) is not an acid. |
What do conjugate pairs differ by? | They differ only by one proton or positively charged ion. |
What is the pH of solution that contains both a strong acid and a strong base? | pH= 7 (neutral) |
What is the pH of a solution that contains a strong acid and a weak base? | pH<7 (acidic) |
When a weak acid is combined with a strong base? | pH>7. (basic) |
Weak acid with a weak base gives a pH of? | You have to look at which one is slightly weaker and then decide. |
What is the job of a buffer system? | To neutralize a solution. Get the pH back to 7. |
What is a buffer solution? | A solution in which resists change in pH upon addition of small amounts of acid or base. Represented as salt/acid or conjugate base/acid. |
Acids want to give up what? Bases want to accept what? | Acids want to give up H+ ions, and a base wants to accept H+ ions. |
What are some buffers and where are they present? | Blood plasma, Carbonic acid (H2CO3) and bicarbonate (HCO3-) |
A pH between 4-10 can adjust__ while a pH above or below that__? | Quickly, above or below cannot adjust as quickly. |
A pH of 7.4=__, while a pH of <7.0=__, and a pH>7.8=__? | 1) neutral 2) life threatening 3) morbidity |
What is the key to regulating pH? | Regulating the H+ ion concentration by the buffer systems. |
What is ECF usually regulated by? | HCO3/CO2--> lungs and the kidneys |
What is ICF usually regulated by? | By proteins & PO4--> Phosphates |
What is the pH of tissues and the pH of Blood? | Tissues are around 6.0 because they can't keep as well of a balance as the blood that usually has a pH around 7.4. |
What are two really important acids? | Carbonic acid (H2CO3) and Non-carbonic acid. |
What is carbonic acid (H2CO3) usually formed from and what does it produce? | The metabolism of carbohydrates,and fats. Usually produces 15,000 mmol of CO2/day. |
What are non-carbonic acids formed from and what do they produce? | Protein metabolism and produce 1.5mmol H+ ions/kg/day. |
Three classifications of buffer systems? | Chemical, Respiratory, Metabolic. |
What type of buffer is in cells & body fluids and reacts immediately? | Chemical Buffer |
This buffer system uses CO2 and reacts within minutes? | Respiratory Buffer |
Metabolic Buffer uses what and when does it react? | HCO3- and reacts within hours. |
Three main systems in the body? | Blood, Respiration, Kidneys |
Acid-Base homeostasis centers around regulation of these? | Blood, Respiration (CO2), and Kidneys (HCO3). |
A good buffer system has equal concentrations of what? | Hydrogen (H+) ions and Hydroxide (OH-) ions. |
It is the buffer present at the highest concentrations in the body? | either or HCO3/CO2 |
HCO3-/CO2 has a pKa value of what? | 6.1 with 50/50 acid/base. Close to 7.4 |
What are the major components of the buffer systems that can independently regulate pH? | Lungs (CO2) and Kidneys (HCO3-) |
A normal meat based diet produces what? | 20,000mEq of acid/day. |
What is the end product of Carbohydrate and fat metabolism and how is it excreted? | CO2 and it is excreted by the lungs. |
Protein catabolism produces what and how is it excreted? | 1 mEq/kg (50-60 mEq/day) of inorganic acids. Controlled by the kidney through formation of HCO3- and excretion. |
Process of the Bicarbonate buffer system in response to what? | (H+) + HCO3 <--> H2CO3 <--> CO2 + H2O. In response to ^ in H+ ions. H+ will bind w/ HCO3 (bicarb) needs carbonic anhydrase to form H2CO3 (carbonic acid). H2CO3 immediately breaks down into H2O & CO2. |
The bicarbonate buffer system increases CO2 in the presence of what, and decreases CO2 in the presence of what? | Increases when there are increased amounts of H+ ions and decreases when there are decreased amount of H+ ions. |
Why is the respiratory system an important part of the Bicarbonate buffer system? | Because it compensates for our CO2 level by changing rate and depth of respiration's to either eliminate excess CO2 or attainment of CO2. |
How does the renal system react in the presence of a decrease in pH? An increase in pH? | Decrease pH the kidney's will increase the secretion of H+ ions in the urine. Increase in pH they will reabsorb H+ ions back into the blood. |
This buffer system may take hours or even days for compensation? | Renal System |
This buffer system prevents drastic changes in plasma CO2? | Hemoglobin (Hgb) buffer system |
What absorbs CO2 in the Hgb buffer system and how do they contribute to compensation? | RBC absorb CO2 and changes it to H2CO3 (carbonic acid) in which quickly dissociates and is excreted via the lungs. |
Describe what happens when the Hgb buffer system compensates by the body producing CO2? | CO2 is dumped in the blood and picked up by RBC. It combines with H2O-> H2CO3 then dissociates -> H+ and HCO3. If HCO3 goes into plasma the RBC takes on Cl-. Once in the lung HCO3 goes into RBC combines w/ H+-> H2CO3-> CO2 & H2O. CO2 is excreted via lungs |
What does the Respiratory buffer system use for compensation? And where does it go? | Carbonic acid/bicarbonate system. CO2 + H2O--> H+ & HCO3--> CO2 & H2O. Goes from muscle to blood plasma to lungs. |
Where do we see the Phosphate buffer system? | ICF and Urine |
What are the main elements of the phosphate buffer system? | H2PO4- and HPO4 |
What happens when a strong acid is added and the phosphate buffer system compensates? | The H+ is accepted by the phosphate base and converted to H2PO4 (weak acid). HCl + Na2HPO4-->NaH2PO4 + NaCl. This rxn decreases the reduction in pH. |
What happens when a strong base is added and the phosphate buffer system compensates? | NaOH + NaH2PO4--> Na2HPO4 + H2O. The strong base is now converted into a weak base causing only a slight increase in pH instead of a drastic increase with the strong base. |
Carotid and aortic sinuses do what to help maintain pH? | Increase BP to area where there is an increase in H+ ions in an attempt to eliminate them, and then increase RR to breath off CO2. |
Receptors in the medulla oblongata help to maintain the pH in what type of fluid? | CSF |
The renal buffering system stops buffering when the urine pH is what? | pH=4.5 |
How does the renal buffer compensate for a high pH if it stops when the pH of urine reaches 4.5 | Buffer phosphates bonds with excess H+ ions in the kidneys, so that the pH still remains low enough for the renal buffer system to excrete H+ ions into the urine, while binding with other H+ ions to form HCO3 that is reabsorbed into the plasma. |
Which is more of a bigger problem, elimination of excess acid or base? | Excess acid |
Where do some of the acids in our body come from? | Normal metabolism, ingested acids. |
There are two forms of acids what are they? | Volatile=(H2CO3) and Nonvolatile= products of metabolism. |
What is an example of a volatile acid? | H2CO3 (carbonic acid)-weak acid. Formed from picking up CO2. Weak acid doesn't release H+ easily, and needs carbonic anhydrase for dissociation--> To make H2O and CO2 |
How is the volatile acid H2CO3 formed in the body and how is it eliminated? | By normal metabolism of fat, carbohydrates, and some proteins. Eliminated by the lungs. |
What are some examples of a non-volatile acid and how are they excreted? | H2SO4, H3PO4, lactic acid/ketoacids. Excreted by the lungs. |
H2SO4 and H3PO4 are formed from what inside our body? | From metabolism of sulfu-containing proteins, and phosphoproteins. |
Lactic acid/ketoacids are the products of? | Intermediary metabolism. Ketoacid is formed from the metabolism of a large amount of fats that are broken down when carbohydrates are not available as an energy source. Lactic acid is formed in the result of Anaerobic metabolism. |
What pH should be maintained if there is a good buffer system? | pH= 7.4 |
What is pKa? | Acid dissociation constant Ka, measure of the strength of acid in a solution. Larger the pKa value the smaller of extent of dissociation of H+ ions from an acid. |
What does pKa measure the tendency of? | The tendency of A molecule or ion to keep a proton (H+). Acids give up H+ and bases steal H+ ion. |
Dissociate almost completely in a solution? | Strong acids almost give up all their H+ ions. |
Strong acids..... | Have large acidity constants, and are close to 1. Eg.HCL pH=2=0.01 |
Do not fully dissociate, and have acidity constants far less than 1. | Weak acids eg. soda pH=4=0.0001 |
Buffers that have a pKa of what are the best? | 7.4 because the H+ and OH- ions are equal. |
These ions move freely between ECF and ICF? | H+ ions |
If a H+ moves from ECF to ICF what has to happen? Think Hgb buffer system. | A negatively charged ion (anion) has to move in the same direction, and a positive ion (cation) has to move in the opposite direction. Increase in Plasma H+, elicits and increase in Plasma K+, and Cl- is pulled out. |
Why is it important to check K+ levels in a person with DKA? | Because in DKA the H+ moves into the cells and K+ moves out of the cells. |
What are the most abundant buffers in and out of cells and why? | Proteins, because the contain the amino acid histidine. |
What is a histidine? | An amino acid in which has an imidazole ring with pKa=7.0. They are really the buffer on proteins. |
Why is Hgb one of the best protein buffer systems? | Because it contain histidines, (36 per molecule) |
Phosphates are buffers that are active in where? | Buffers in which are active in the kidney. |
Are phosphates in ICF or ECF? | They are present in large amounts inside cells, and small amounts in the ECF. |
What is the pKa of the phosphate buffer system (HPO4+, H2PO4-)? | pKa=6.8 |
With the bicarbonate buffer system we get rid of the acid, but we also lose what? | We also lose bicarbonate. |
How does our body replace the bicarbonate? | It is regenerated in the bone stores of carbonate, and the kidney is able to regenerate new bicarbonate to replace which was lost. |