indikator Asam Basa
Telah disebutkan bahwa asam telah mempunyai rasa asam, sedangkan basa telah mempunyai rasa pahit. Namun begitu, tidak dianjurkan untuk dapat mengenali asam dan basa dengan, cara mencicipinya, sebab banyak diantaranya yang dapat merusak kulit (korosif) atau bahkan bersifat racun. Asam dan basa juga dapat dikenali dengan menggunakan zat indikator, yaitu zat yang telah meniberi warna berbeda dahlia) lingkungan asam dan lingkungan basa (zat yang warnanya dapat berubah saat berinteraksi atau bereaksi dengan senyawa asam maupun senyawa basa).
Dalam laboratorium kimia, indikator asam-basa yang biasa di gunakan adalah indikator buatan dan indikator alami, Berikut ini penjelasan tentang indikator asam-basa buatan dan indikator asam-basa alami.
Derajat keasaman (pH)
Indikator Tingkat Keasaman Suatu zat asam yang di masukkan ke dalam air akan dapat mengakibatkan bertambahnya ion hidrogen (H+) dalam air dan berkurangnya ion hidroksida (OH- ). Sedangkan pada basa, akan dapat terjadi sebaliknya. Zat basa yang dimasukkan ke dalam air akan dapat mengakibatkan bertambahnya ion hidroksida (OH- ) dan berkurangnya ion hidrogen (H+).
Jumlah ion H+ dan OH- di dalam air dapat di gunakan untuk dapat menentukan derajat keasaman atau kebasaan suatu zat. Semakin asam suatu zat, semakin banyak ion H+ dan semakin sedikit jumlah ion OH- di dalam air. Sebaliknya semakin basa suatu zat, semakin sedikit jumlah ion H+ dan semakin banyak ion OH- di dalam air.
Apabila suatu larutan asam dengan larutan basa akan dicampurkan dalam suatu bejana, maka ion H+ (dari asam) akan bereaksi dengan ion OH- (dari 311 basa) membentuk air. Reaksi antara ion H+ dengan OH- tersebut juga dapat di tuliskan sebagai berikut. H+ + OH- air
ini karena selain air, basil reaksi antara asam dan basa adalah suatu zat yang bersifat netral, yaitu zat yang tidak bersifat asam maupun basa. Zat netral yang di maksudkan di sini adalah garam. Mengingat reaksi netralisasi juga dapat menghasilkan garam, maka reaksi ini juga di kenal dengan istilah reaksi penggaraman. Secara sederhana, reaksi netralisasi atau reaksi penggaraman juga dapat di tuliskan sebagai berikut.
Contoh sederhana dari reaksi penggaraman adalah reaksi antara asam klorida (HC1) dengan natrium hidroksida (NaOH), yang akan dapat membentuk natrium klorida NaCl (garam dapur) dan air. Pada dasarnya, reaksi penggaraman (netralisasi) juga sangat berguna bagi kehidupan manusia.
Reaksi netralisasi tidak hanya terbatas pada pembentukkan garam dan air. Dalam kehidupan sehari-hari banyak dijumpai prinsip atau reaksi netralisasi, termasuk dalam bidang kesehatan dan pertanian. Perhatikan contoh berikut ini : gas-gas sisa, baik yang berasal dari kendaraan bermotor atau pabrik, mengandung gas belerang dioksida dan nitrogen oksida.
Gas-gas ini akan dilepas ke udara sehingga menimbulkan polusi. Gas-gas tersebut juga akan larut dalam titik-titik air di awan sehingga membentuk larutan asam sulfat dan asam nitrat. Ketika terjadi hujan, larutan-larutan ini akan bercampur dan turun bersama hujan. Inilah yang dinamakan dengan hujan asam.
Hujan asam sangat merugikan manusia dan lingkungan. Berikut adalah dampak yang ditimbulkan oleh hujan asam:
Hujan asam dapat menyebabkan matinya tumbuhan dan ikan. Asam yang telah terdapat dalam air hujan juga dapat bereaksi dengan mineral dalam tanah. Tumbuhan akan menjadi kekurangan mineral sehingga mati atau tidak tumbuh dengan baik. Hujan asam juga dapat melarutkan aluminium dari mineral dalam tanah dan bebatuan, kemudian menghanyutkannya ke sungai sehingga dapat meracuni ikan dan mahluk air lainnya.
Hujan asam yang bereaksi dengan logam juga dapat merusak jembatan, mobil, kapal laut, dan rangka bangunan. Hujan asam juga dapat merusak bangunan (gedung/ rumah) yang terbuat dari batu kapur.
INDIKATOR ASAM BASA
Editor : Dian Sukmawati
Even as a high school student, Dave Goldberg was urging female classmates to speak up. As a young dot-com executive, he had one girlfriend after another, but fell hard for a driven friend named Sheryl Sandberg, pining after her for years. After they wed, Mr. Goldberg pushed her to negotiate hard for high compensation and arranged his schedule so that he could be home with their children when she was traveling for work.
Mr. Goldberg, who died unexpectedly on Friday, was a genial, 47-year-old Silicon Valley entrepreneur who built his latest company, SurveyMonkey, from a modest enterprise to one recently valued by investors at $2 billion. But he was also perhaps the signature male feminist of his era: the first major chief executive in memory to spur his wife to become as successful in business as he was, and an essential figure in “Lean In,” Ms. Sandberg’s blockbuster guide to female achievement.
Over the weekend, even strangers were shocked at his death, both because of his relatively young age and because they knew of him as the living, breathing, car-pooling center of a new philosophy of two-career marriage.
“They were very much the role models for what this next generation wants to grapple with,” said Debora L. Spar, the president of Barnard College. In a 2011 commencement speech there, Ms. Sandberg told the graduates that whom they married would be their most important career decision.
In the play “The Heidi Chronicles,” revived on Broadway this spring, a male character who is the founder of a media company says that “I don’t want to come home to an A-plus,” explaining that his ambitions require him to marry an unthreatening helpmeet. Mr. Goldberg grew up to hold the opposite view, starting with his upbringing in progressive Minneapolis circles where “there was woman power in every aspect of our lives,” Jeffrey Dachis, a childhood friend, said in an interview.
The Goldberg parents read “The Feminine Mystique” together — in fact, Mr. Goldberg’s father introduced it to his wife, according to Ms. Sandberg’s book. In 1976, Paula Goldberg helped found a nonprofit to aid children with disabilities. Her husband, Mel, a law professor who taught at night, made the family breakfast at home.
Later, when Dave Goldberg was in high school and his prom date, Jill Chessen, stayed silent in a politics class, he chastised her afterward. He said, “You need to speak up,” Ms. Chessen recalled in an interview. “They need to hear your voice.”
Years later, when Karin Gilford, an early employee at Launch Media, Mr. Goldberg’s digital music company, became a mother, he knew exactly what to do. He kept giving her challenging assignments, she recalled, but also let her work from home one day a week. After Yahoo acquired Launch, Mr. Goldberg became known for distributing roses to all the women in the office on Valentine’s Day.
Ms. Sandberg, who often describes herself as bossy-in-a-good-way, enchanted him when they became friendly in the mid-1990s. He “was smitten with her,” Ms. Chessen remembered. Ms. Sandberg was dating someone else, but Mr. Goldberg still hung around, even helping her and her then-boyfriend move, recalled Bob Roback, a friend and co-founder of Launch. When they finally married in 2004, friends remember thinking how similar the two were, and that the qualities that might have made Ms. Sandberg intimidating to some men drew Mr. Goldberg to her even more.
Over the next decade, Mr. Goldberg and Ms. Sandberg pioneered new ways of capturing information online, had a son and then a daughter, became immensely wealthy, and hashed out their who-does-what-in-this-marriage issues. Mr. Goldberg’s commute from the Bay Area to Los Angeles became a strain, so he relocated, later joking that he “lost the coin flip” of where they would live. He paid the bills, she planned the birthday parties, and both often left their offices at 5:30 so they could eat dinner with their children before resuming work afterward.
Friends in Silicon Valley say they were careful to conduct their careers separately, politely refusing when outsiders would ask one about the other’s work: Ms. Sandberg’s role building Facebook into an information and advertising powerhouse, and Mr. Goldberg at SurveyMonkey, which made polling faster and cheaper. But privately, their work was intertwined. He often began statements to his team with the phrase “Well, Sheryl said” sharing her business advice. He counseled her, too, starting with her salary negotiations with Mark Zuckerberg.
“I wanted Mark to really feel he stretched to get Sheryl, because she was worth it,” Mr. Goldberg explained in a 2013 “60 Minutes” interview, his Minnesota accent and his smile intact as he offered a rare peek of the intersection of marriage and money at the top of corporate life.
While his wife grew increasingly outspoken about women’s advancement, Mr. Goldberg quietly advised the men in the office on family and partnership matters, an associate said. Six out of 16 members of SurveyMonkey’s management team are female, an almost unheard-of ratio among Silicon Valley “unicorns,” or companies valued at over $1 billion.
When Mellody Hobson, a friend and finance executive, wrote a chapter of “Lean In” about women of color for the college edition of the book, Mr. Goldberg gave her feedback on the draft, a clue to his deep involvement. He joked with Ms. Hobson that she was too long-winded, like Ms. Sandberg, but aside from that, he said he loved the chapter, she said in an interview.
By then, Mr. Goldberg was a figure of fascination who inspired a “where can I get one of those?” reaction among many of the women who had read the best seller “Lean In.” Some lamented that Ms. Sandberg’s advice hinged too much on marrying a Dave Goldberg, who was humble enough to plan around his wife, attentive enough to worry about which shoes his young daughter would wear, and rich enough to help pay for the help that made the family’s balancing act manageable.
Now that he is gone, and Ms. Sandberg goes from being half of a celebrated partnership to perhaps the business world’s most prominent single mother, the pages of “Lean In” carry a new sting of loss.
“We are never at 50-50 at any given moment — perfect equality is hard to define or sustain — but we allow the pendulum to swing back and forth between us,” she wrote in 2013, adding that they were looking forward to raising teenagers together.
“Fortunately, I have Dave to figure it out with me,” she wrote. Dave Goldberg Was Lifelong Women’s Advocate