题型:问答题 简答题 Although _____ my opinion, the old professor didn't come up with his own. [ ]A. against B. on C. for D. in 查看答案
题型:问答题 简答题 用热气灶烧水,燃烧0.6kg的煤气,使50kg的水从20℃升高到80℃,已知煤气的热谊为4.2×107J/kg.求:(1)煤气完全燃烧放出的热量.(2)水吸收的热量.(3)燃气灶烧水的效率. 查看答案
题型:问答题 简答题 计算题;已知35钢的液相线温度是1509℃,钢种的过热度取30℃,精炼过程的温降为15℃,浇注过程温降是60℃,精炼完毕至开浇的温降是5℃。求精炼开始时钢液的温度是多少? 查看答案