【简答题】收款凭证、付款凭证是出纳人员收款、付款的依据。( )
【单选题】A student claimed that “If the masses of 1 cm3of any solid and 1 cm3of any liquid are compared, the massof the solid will be greater.” Do the data in Table 1support his claim?
A.
No; lead has a higher density than any of the liq-uids listed.
B.
No; mercury has a higher density than any of the solids listed.
C.
Yes; lead has a higher density than any of the liq-uids listed.
D.
Yes; mercury has a higher density than any of the solids listed.
【简答题】The World Health Organization says its ten-year campaign to remove leprosy as a world health problem has been successful. Doctor Brundtland, head of the WHO, says a number of leprosy cases around the ...
【单选题】党的十九大报告指出,( )是激励全党全国各族人民奋勇前进的强大精神力量。
【单选题】医药上常用做消毒剂和防腐剂的福尔马林是40%的( )水溶液。
【简答题】某化学兴趣小组用甲、乙两套装置(如图所示)进行甲酸(HCOOH)与甲醇(CH 3 OH)酯化反应的实验,该有机产物在医药上,常用作磺酸甲基嘧啶、磺酸甲氧嘧啶、镇咳剂美沙芬等药物的合成原料.回答以下问题: (1)甲酸和甲醇进行反应的化学方程式是:______. (2)乙装置中长玻璃导管c的作用是______;冷凝水应该从______进入. (3)接收器中饱和碳酸钠溶液的作用是______; (4)甲...
【简答题】阿司匹林是日常生活中应用广泛的医药之一。它可由下列方法合成: 下列说法正确的是 A.邻羟基苯甲醇分子中所有的原子不可能在同一平面 B.用酸性KMnO 4 溶液直接氧化邻羟基苯甲醛可实现反应① C.反应②中加入适量的NaHCO 3 可提高阿司匹林的产率 D.与邻羟基苯甲酸互为同分异构体,苯环上一氯代物仅有2种且能发生银镜反应的酚类化合物共有2种