第二章第三节第1课时知能演练轻松闯关一、单项选择题1.模型法是化学中把微观问题宏观化的最常见方法，对于2HBr(g)H 2(g)＋Br 2(g)反应。
下列四个图中可以表示该反应在一定条件下为可逆反应的是( )解析：选C 。
C 项说明三种物质共存，是可逆反应。
2.298 K 时，合成氨反应的热化学方程式为：N 2(g)＋3H 2(g) 2NH 3(g) ΔH ＝－92.4 kJ/mol ，在该温度下，取1 mol N 2和3 mol H 2放在密闭容器内反应。
下列说法正确的是( )A ．在有催化剂存在的条件下，反应放出的热量为92.4 kJB ．有无催化剂该反应放出的热量都为92.4 kJC ．反应放出的热量始终小于92.4 kJD ．若再充入1 mol H 2，到达平衡时放出的热量应为92.4 kJ解析：选C 。
该反应为可逆反应，正向不可能进行到底，所以1 mol N 2和3 mol H 2反应放出的热量始终小于92.4 kJ ，C 正确。
3.对于恒容密闭容器中发生的可逆反应N 2(g)＋3H 2(g) 2NH 3(g) ΔH <0，能说明反应达到化学平衡状态的为( )A ．断开一个N ≡N 键的同时有6个N —H 键生成B ．混合气体的密度不变C ．混合气体的平均相对分子质量不变D ．N 2、H 2、NH 3分子数比为1∶3∶2的状态解析：选C 。
断开N ≡N 键与生成N —H 键是同一个反应方向，A 不对；平均相对分子质量M r ＝m n，反应过程中m 始终不变，若M r 不变，则n 不变，说明反应已达平衡。
密闭容器混合气体密度始终不变。
4.在2NO ＋O 22NO 2(正反应为吸热反应)的反应中，如图所示表明在30 ℃和100 ℃时的平衡体系中，NO 的百分含量与压强(p )或压强一定时与时间的关系图像。
其中正确的是( )解析：选D。
当温度不变时，增大压强平衡向正反应方向移动，NO的百分含量应减小，故A错；当压强一定时，升高温度能够缩短到达平衡所需的时间，故B错；升高温度平衡向正反应方向移动，达到新平衡时，NO的百分含量降低，故C错。
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1.下列说法中，正确的是( )A ．氧化剂本身被还原，生成氧化产物B ．氧化剂是在反应中得到电子(或电子对偏向)的物质C ．还原剂在反应时所含元素的化合价降低D ．在一个反应中，氧化剂和还原剂不可能是同一物质解析：选B 。
氧化剂本身被还原，应生成还原产物，A 错；还原剂在反应时所含元素的化合价应升高，C 错；在一个反应中，氧化剂和还原剂可能是同一物质，如氯酸钾分解制备氧气，氯酸钾既是氧化剂又是还原剂，D 错。
2.(2012·焦作高一检测)下列微粒中，只有氧化性的是( )①S 2－ ②Fe 2＋ ③Fe 3＋ ④S ⑤H ＋ ⑥Na ＋ ⑦MgA ．①⑦B ．②④C ．③⑤⑥D ．②④⑤⑥解析：选C 。
元素在最高价时只有氧化性。
S 2－在最低价，Fe 2＋处于中间价，Fe 3＋是最高价，S 在中间价态，H ＋在最高价，Na ＋在最高价，Mg 处于最低价，所以选C 。
3.需加入适当的氧化剂才能实现的反应是( )A ．PCl 3―→PCl 5B ．MnO －4―→Mn 2＋C ．SO 2―→SO 2－3D ．Fe 3O 4―→Fe 解析：选A 。
A 中，PCl 3―→PCl 5，P 的化合价升高，被氧化，需加氧化剂才能实现；B 中Mn 元素和D 中的Fe 元素化合价均降低，被还原，需加还原剂才能实现；C 中元素化合价未发生变化。
4.下列叙述正确的是( )A ．元素的单质一定由氧化或还原该元素的化合物制得B ．在化学反应中，得电子越多的氧化剂，其氧化性就越强C ．阳离子只能得到电子被还原，阴离子只能失去电子被氧化D ．含有最高价元素的化合物不一定具有很强的氧化性解析：选D 。
A 中存在2O 3======放电3O 2反应，不合题意，故错误；B 中氧化性强弱与得电子的多少无关，而是体现在得电子的能力强弱；C 中Fe 2＋可被氧化，也可被还原；D 中Na 2SO 4含有＋6价的硫，但没有强氧化性。
Ⅰ.阅读理解ADid you know that badminton is also a fastpacedcompetitive sport? Badminton has been a Summer Olympic sportsince 1992. Para-badminton will be included in the comingSummer Olympic Games in Tokyo. Here's what you need toknow if your child is interested in badminton.Badminton is played on a 44footlong rectangular (矩形的) court that is 17 feet wide for singles and 20 feet wide for doubles. It is divided in the middle by a net placed 5 feet off the ground, like volleyball, not at ground level like tennis.In competition, each match is a set of three games played to 21 points. There is a one-minute break when a player or team reaches 11 points, and a twominute break in between the first and second games and the second and third games.Age kids can start: About 6 years old.Best for kids who: Have good skills, are patient and hardworking, and can handle the pressure of oneonone or twoontwo competition.Team or individual: Matches can be singles (one-on-one) or doubles (two-on-two)．Fun fact: Badminton is the only sport that has mixed doubles event in the Olympic Games.Costs: Beginners are expected to pay $30 to $40 for an entry-level racquet (球拍). Badminton shoes are similar in price to other athletic shoes. Join a club or team for lessons. A one-hour group lesson for beginners should cost $20 to $25, with costs increasing as your child moves up the ranks. You will also pay entry fees for competitions.Time commitment required: Beginners will play for just an hour or two per week.Potential for injury: Players have a very low risk of injury. Players who wear glasses should use eye protection.【解题导语】本文是一篇应用文。
