Ammоnium nitrаte is quite sоluble in wаter, аnd the reactiоn of ammonium nitrate with water to produce ammonium nitrate solution is endothermic. We can therefore conclude that
Chооse the sentence with the mоst effective vаriety in structure: а. The cаt sat on the mat. The dog lay by the fire. The bird perched on the windowsill.b. While the cat sat on the mat, the dog lay by the fire; the bird perched on the windowsill.c. The cat, sitting on the mat, watched the dog lying by the fire and the bird perching on the windowsill.d. Sitting on the mat was the cat; by the fire, the dog lay; on the windowsill perched the bird.
TECH JOBS IN JUST FIVE MONTHS Ecоnоmists аnd technоlogists аgree thаt in the future, just about everyone's job will involve more technology. During the last few years, many local and online schools have popped up to teach people how to code. They offer a vast range of prices and techniques. Some, like Codecademy, are free, while others can cost thousands or even tens of thousands of dollars. Some offer more personalized coaching, while others leave students to figure things out on their own. Now Udacity, a four-year-old online teaching start-up, believes that after years of trial and error, it has hit on a model of vocational training that can be scaled up to teach millions of people technical skills. Udacity's founder, Sebastian Thrun, a specialist in artificial intelligence at Stanford University who once ran Google X, the search company’s advanced projects division, said that the “nanodegree” program that the firm created last year will result in vastly lower education costs and wider accessibility. Early data suggests the program is efficient and reliably results in new jobs. The nanodegree works like this: Last year, Udacity partnered with technology companies to create online courses geared toward teaching a set of discrete, highly prized technical skills, including mobile programming, data analysis and web development. Students who complete these courses are awarded the nanodegree, a credential Udacity has worked on with Google. “We don’t turn you into a Nobel laureate,” Thrun told me. ''We offer ‘upskilling’: you’re smart but your skills are inadequate for the current job market, or don't let you get the job you aspire to. We help you get those skills.” If predictions about the potential for technology to substantially improve education smell to you like Silicon Valley peyote, I don't blame you. Computers have long been held up as a magic bullet for learning, and they've constantly failed to deliver; higher education has only become more expensive and less accessible alongside the rise of digital technology. Udacity itself has been beached on the shores of unrealized optimism. In 2011, after discovering wide interest in online learning when he put his Stanford artificial-intelligence lectures online, Thrun founded Udacity as one of the first for-profit MOOCs ('massive open online courses). Initially, Udacity tried to offer students a broad, general-purpose education, attracting many students almost all of whom failed to complete the work. So in 2013, Thrun reimagined Udacity as a practical vocational school offering highly structured lessons to help people find jobs. In an economy constantly riven by technological change, Thrun believes periodic vocational training will become increasingly important in the job market. “It’s a mistake to think that a single college education can carry you for a lifetime,” he said. “To keep pace with change, your education has to be done throughout your life.” So far, Udacity’s new model shows a glimmer of success. One year into the new program, 10,000 students are enrolled in nanodegree courses, and the number increases by a third every month. Udacity charges $200 a month per course and get half of it back when they complete one; they can take as little or as much time as they want to finish). The company says that a typical student earns a nanodegree in about five months – around $500. Because students take months or longer to complete their degrees, it is too soon to tell exactly how many will finish. So far, Udacity estimates the graduation rate is 25 percent. Thousands have earned degrees; hundreds have found new jobs as a result. Several students describe Udacity as life-changing. Dan Haddigan, 28, graduated from art school and worked for several years at an art gallery. Last year, he heard about Udacity The nanodegree in coding was challenging. “I’d wake, do Udacity work, go to the gallery, come home, do more Udacity work.” Five months and $500 later, with a degree, he applied for a web development agency job. Pessimistic, he thought, “Who am I? I just took an online course. They’re going to laugh at me.” They didn’t. He got the job.