1) Почему удельная теплота сгорания сырых дров меньше, чем удельная теплота сгорания тех же дров после просушки?

2) До какой температуры можно нагреть 20 л воды, температура которой 20 градусов, сжигая бензин массой 20г? Считайте, что все колличество теплоты выделевшееся при сгорании бензина, идет на нагревание воды.

3) В алюминевом чайнике массой 900г нагрели 10 л воды до кипения, израсходовав природный газ массой 200 г. Опреелите начальную температуру воды. КПД горелки считайте равным 40% .

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SCHOOLS IN BRITAIN
Ted and Mark go to a typical British school. When they were eleven, they left their primary school and went to the secondary school. Now they are thirteen and they are in year 8. British schoolchildren study the same subjects and have the same lessons until they are thirteen. At thirteen they choose the subjects they want to do for the national GCSE (General Certificate in Secondary Education) exams. They take these exams in year 11 (at the age of sixteen). British children should take national exams in six subjects, although they might take more. Then they might stay at school for two more years and study for two or more 'A level exams. But they might leave school after their GCSEs. Ted and Mark are doing eight subjects. They have to study English and Maths, and they have chosen French, Physics, Biology, Chemistry, Art and Design, and Information Technology. Their classmates I chose different subjects so they don't have many lessons together even though they are still in the same form. They're taking their GCSE exams in June. They also do PE but there isn't a PE exam. Ted and Mark go to school from Monday to Friday. School starts at 9 o'clock. There is a 20 minute break at half past 10. They have lunch at one o'clock. A few people go home but most of them eat lunch in the canteen. Afternoon lessons start at quarter to 2 and finish at quarter to 4. After school the boys do sport. In their school pupils can also join the music group or belong to a club. When they get home they have to do their homework. They like their school but Ted hates the uniform they have to wear. After school the boys would like to go to a university but none of them decided what they want to study yet.

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