Thursday, February 20, 2020

Formation of Isoamyl Acetate Lab Report Example | Topics and Well Written Essays - 250 words

Formation of Isoamyl Acetate - Lab Report Example During reflux a colour change from colourless to slight yellow was observed. After 15 minute reflux the mixture was allowed to cool and 1M sodium hydroxide solution was used for the neutralisation. Strong banana smell was detected. To the obtained solution a portion of diethyl ether was added. As two layers formed, sparatory funnel was used to remove the diethyl ether layer. Extraction was conducted several times after which all the produced diethyl ether layers were combined, dried and heated until all diethyl layer evaporated. The described manipulations afforded 1.52 g. of isoamyl ester (25.42%). It is expected that the boiling point of isoamyl acetate will be 1420C, however this temperature will be lower of traces of diethyl ether remained. Regarding IR results, it is expected that there will be no signals in the region 3000-4000 cm-1. If there are then traces of acetic acid or alcohol remained in the product. Also, characteristic signals in the region 1500-2000 cm-1 should point out to the presence of C=O group. The fingerprint region should be compared with the isoamyl acetate spectrum from the database (Clayden, et al.,

Tuesday, February 4, 2020

A study of communication strategies employed by Chinese EFL learners Literature review

A study of communication strategies employed by Chinese EFL learners in oral contexts - Literature review Example ?....14 2.4 Communication Problems of Chinese EFL Learners†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦..15 References†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦17 1. Introduction For communication to take place, a message needs to be transferred from the sender to the receiver. But sometimes the communication process may break down when the intended message fails to be sent to the receiver. In those situations, the speaker will try to solve the problem and re-establish the conversation by adopting certain techniques. These techniques are commonly known as â€Å"communication strategies† (CSs). It was a term firstly coined by Selinker (1972) in his paper on â€Å"Interlanguage†. Selinker considered these strategies as one of the five processes central to second language learning. All language us ers need communication strategies to help them convey their intended meaning. ... The time constraints of naturally-occurring conversations impose an extremely heavy burden on these learners, forcing them to retrieve appropriate TL items from their memory and respond quickly. As claimed by Wagner and Firth (1997), â€Å"CS is a very prominent element in speech production and therefore an important element in natural discourse† (p. 342). 1.1 Definitions In the past three decades, a great amount of scholarly research and discussion has been generated on the nature, taxonomies and use of CSs (Dornyei and Scott, 1997). For so many years, however, the definition of CSs has still remained controversial. Although Selinker was the first to put forward the term â€Å"communication strategy†, he did not dig deep into the nature of such strategies. The first ones to provide a definition of CS were Tarone and her associates (1976), who defined it as â€Å"a systematic attempt by the learner to express or decode meaning in the target language, in situations wher e the appropriate systematic target language rules have not been formed† (p. 78). Moreover, Tarone (1980) emphasized that â€Å"CS relate to a mutual attempt of interlocutors to agree on a meaning in situations where requisite meaning structures do not seem to be shared† (p. 420). This definition introduces an interactional perspective. In Tarone’s words, â€Å"communication strategies are seen as tools used in a joint negotiation of meaning where both interlocutors are attempting to agree as to a communicative goal† (p. 420). Simply put, it means that both parties in the communication process try to compromise on meaning by adjusting their perspectives to see just one meaning both of them understand, and this may include some repair mechanisms in the breakdown of