Henderson Hasselbalch Equation Definition

Henderson Hasselbalch Equation Definition The Henderson Hasselbalch equation is an approximate equation that shows the relationship between the pH or pOH of a solution and the pKa or pKb and the ratio of the concentrations of the dissociated chemical species. In order to use the equation, the acid dissociation constant must be known. Equation There are multiple ways to write the equation. Two of the most common are: pH pKa log ([conjugate base]/[weak acid]) pOH pKa log ([conjugate acid]/[weak base]) History An equation to calculate the pH of a buffer solution was derived by Lawrence Joseph Henderson in 1908. Karl Albert Hasselbalch rewrote this formula in logarithmic terms in 1917. Sources Hasselbalch, K. A. (1917). Die Berechnung der Wasserstoffzahl des Blutes aus der freien und gebundenen Kohlensure desselben, und die Sauerstoffbindung des Blutes als Funktion der Wasserstoffzahl. Biochemische Zeitschrift. 78: 112–144.Henderson, Lawrence J. (1908). Concerning the relationship between the strength of acids and their capacity to preserve neutrality. Am. J. Physiol. 21: 173–179.

Explanation of Newspaper Headlines for English Learners

Explanation of Newspaper Headlines for English Learners Many students have difficulty understanding newspaper headlines. This is because newspaper headlines are often incomplete sentences (i.e. Difficult Times Ahead). Here is a guide to the most common exceptions found in newspaper headlines. Noun Phrases Headlines often contain a noun phrase with no verb. A noun phrase describes a noun (i.e. around strange, exotic people). Here are some examples of noun phrase headlines: Under Pressure from BossUnexpected VisitOverwhelming Response of Voters Its useful to ask yourself questions such as: From what? About what? From whom? To whom? etc. when reading these type of headlines. By asking yourself these questions, you can begin preparing yourself for the article. This practice helps the brain prepare itself by starting to think about vocabulary related to the subject. Heres an example: Unexpected VisitThe questions I can ask myself are: From whom? Why was the visit unexpected? Who was visited? etc. these questions will help focus my mind on vocabulary related to relationships, traveling, surprises, important reasons for visits, etc. Noun Strings Another common headline form is a string of three, four or more nouns together (i.e. Country Leader Question Time). These can be difficult because the words dont appear related by verbs or adjectives. Here are some more examples: Widow Pension Pay CommitteeLandscaping Company Disturbance RegulationsMustang Referral Customer Complaint In the case of noun strings, its helpful to try to connect the ideas by reading backward. For example: Mustang Referral Customer ComplaintBy reading backward, I can guess that: There is a complaint made by a customer about a referral program for Mustang cars. Of course, you need to use your imagination for this! Various Verb Changes There are a number of verb changes made to headlines. The most common are: Simple tenses used instead of continuous or perfect forms. For example:Â  Forgotten Brother Appears A forgotten brother has appeared (after a long period of time).Professors Protest Pay Cuts Professors are protesting pay cuts (at the university). The infinitive form refers to the future. For example:Â  Mayor to Open Shopping Mall The mayor is going to open a new shopping mall.James Wood to Visit Portland (Famous actor) James Wood is going to visit Portland soon. Auxiliary verbs are dropped in the passive form. For example:Â  Man Killed in Accident A Man has been killed in an accident.Tommy the Dog Named Hero Tommy the Dog has been named a hero (by the mayor). Drop Articles Perhaps you have noticed in the examples above that both definite and indefinite articles are also dropped in newspaper headlines (i.e. Mayor to Choose Candidate). Here are some more examples: President Declares Celebration The president has declared a celebration.Passerby Sees Woman Jump A passerby has seen a woman jump (into the river).