问题 填空题

在一固定容积的密闭容器中,保持一定温度,在一定条件下进行以下反应:A(g)+2B(g)3C(g),已知加入1 molA和3molB且达到平衡后,生成了amol C。

(1)达到平衡时,C在反应混合气体中物质的量分数为_______________(用字母a表示)。

(2)在相同实验条件下,若在同一容器中改为加入2molA和6molB,达到平衡后,C的物质的量为

________mol(用字母a表示)。此时C在反应混合气体中物质的量的分数_______________。(填“增大”、“减小”或“不变”)

(3)在相同实验条件下,若在同一容器中改为加入2molA和8molB,若要求平衡后C在反应混合气体中体积分数不变,则还应加入C_____________mol。

答案

(1)25a%

(2)2a;不变

(3)6

单项选择题
填空题

Many animals engage in play,but homo sapiens is the only animal (1) have invented sports.Since sports are an invention,a part of culture (2) than an aspect of nature,all definitions of sports are somewhat arbitrary. (3) sports are a human universal found in every known culture or a (4) unique to modern society depends upon one’s definition of sports.Men and (5) have always run,jumped,climbed,lifted,thrown, and wrestled,but they have (6) always performed these physical activities competitively. Although all literate societies seem to (7) contests of one sort or another in which men, and sometimes women, (8) in displays and tests of physical skill and prowess,sports may be (9) defined as physical contests performed for their own sake and not for (10) ulterior end.According to this strict definition,neither Neolithic hunters nor contestants (11) religious ceremonies such as the ancient Olympic Games were engaged in sports. (12) on the stipulation that sports must be performed for their own sake (13) the paradoxical elimination of many activities which are usually thought of as (14) ,such as exercises done for the sake of cardiovascular fitness,races run (15) satisfy a physical education requirement,ball games played to earn a paycheck. (16) definition also means abandonment of the traditional usage in which"sport,"derived (17) Middle English disporter,refers to any light hearted recreational activity.In the. (18) of some 18th- century aristocrats,a game of backgammon and the seduction of (19) milkmaid were both considered good sport,but this usage of the term (20) become archaic.