题干


某探究小组利用丙酮的溴代反应:
(CH3COCH3+Br2CH3COCH2Br+HBr)来研究反应物浓度与反应速率的关系。反应速率v(Br2)通过测定溴的颜色消失所需的时间来确定。在一定温度下,获得如下实验数据。分析实验数据所得出的结论不正确的是
实验
序号
初始浓度c/mol??L1   K^S*5U.C#
溴颜色消失
所需时间t/s
CH3COCH3
HCl
Br2

0.80
0.20
0.0010
290

1.60
0.20
0.0010
145

0.80
0.40
0.0010
145

0.80
0.20
0.0020
580
 

A:增大c(CH3COCH3),v(Br2)增大

B:实验②和③的v(Br2)相等

C:增大c(HCl),v(Br2)增大

D:增大c(Br2),v(Br2)增大

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答案(点此获取答案解析)

D

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    Leaving Hanoi on a fiercely hot summer day,after an hour by air,Luang Prabang gradually appears below our airplane wings.From a few hundred meters above,my first impression of this UNESCO-listed heritage(遗产)is an area of green land and mountains,surrounded by snaking rivers.

    Encircled by mountains,the former royal capital of Luang Prabang is more than just the country's picture-perfect showpiece.

    Travelers will be attracted to Luang Prabang by the city's timeless peacefulness with its shiny Buddhist temples, French colonial architecture and friendly people.

    Tourists visiting Luang Prabang shouldn't miss the chance to see one of the most sacred(神圣的)Lao traditions, tak bat,or the Buddhist almsgiving ritual(仪式),which dates back to the 14th century.

    As the sun rises in Luang Prabang,hundreds of Buddhist monks depart from their temples to gather their daily offerings,which most commonly are rice,fresh fruit and traditional sweet snacks.The daily alms gathering begins on the main street before spreading to all the side streets.

    Our group of six got out of our comfy beds at 5 am to join other local residents and tourists to offer alms to the monks.We kneeled by the roadside in front of the 3 Nagas Hotel on the main street with big baskets of steamed sticky rice,waiting quietly until monks of all ages passed by to accept our gifts.

    The daily ritual gives you a wonderful opportunity to experience an ancient Lao tradition.However,there are some strict rules if you wish to join the event.

    Firstly,shoulders,chests and legs must be covered in modest clothing as a mark of respect.You should also remain a suitable distance from the monks.Photographs may be taken,but from a distance and never use a camera flash.The ritual has to be performed in silence.Talking to or touching the monks at any time,even when making an offering,is not allowed.

    Another must-do morning activity is to visit the local market,where you can see the generosity that Mother Nature offers this dreamy land.While walking through the morning market,located within a long and narrow hamlet,I was excited to see all kinds of products from the nearby river and jungle: some ill-fated squirrels lying next to fresh bamboo shoots,different kinds of wild mushrooms and vegetables displayed on banana leaves and giant river catfish in baskets.

    Although Luang Prabang is small,there are many things to see here.Active travelers can get up close and personal with Laos' gentle giants at the elephant conservation camp or take in some scenes of riverside life with a cruise or kayak excursion on the rivers.Two waterfalls that are perfect for picnicking in the foothills nearby,and classes are available in traditional crafts.