某中学为学生供应开水，用焦炭作为燃料，已知焦炭的热值是3×107J/kg，现完全燃烧了4.2kg的焦炭，放出的热量____ J；设该热量有25%被水吸收，能将____ kg的水从25℃加热到100℃。C水=4.2×103J/（kg·℃）
He is organized and is often . I hope he will have more at his business.
