问题 多选题

甲烷是一种清洁燃料.某密闭容器中有甲烷(CH4)、氧气和二氧化碳三种物质,在一定条件下充分反应,测得反应前后各物质的质量如下表.根据表中信息,判断下列说法正确的是(  )

物质CH4O2CO2H2O
反应前质量/g167010
反应后质量/g0X4536

A.日常燃烧甲烷不会产生温室气体

B.表中“X”值为6g

C.该反应为分解反应

D.16g甲烷在50g氧气中燃烧会生成CO、CO2、H2O

答案

A、甲烷燃烧生成二氧化碳和水,二氧化碳属于温室效应的主要气体,故A错;

B、根据质量守恒定律可以知道,X=16+70+1+0-0-45-36=6,故B正确;

C、甲烷反应后质量减少属于反应物,反应后氧气质量减少,属于反应物,二氧化碳反应后质量增加,属于生成物,开始没有水,最后有水了,说明水是生成物,反应物是两种,生成物是两种,所以该反应不是分解反应,故C错;

D、根据CH4+2O2

点燃
.
CO2+2H20

16 64

由上面的数据可知16g甲烷与64g氧气恰好完全反应,16g甲烷在50g氧气中燃烧时,氧气不充足,不仅产生二氧化碳和水,还会产生一氧化碳,故D正确.

故选:BD.

阅读理解

In this century the traditional American family is constantly faced with the threat of breakdown. Some sociologists suggest that one little-noticed cause may be the introduction of the TV dinner.

Before the appearance of television sets, the American dinner was a big event for the family. In many homes, dinner time may be the only time when everyone got together. A typical dinner was usually in three stages. In the preparation stage, the children and Father frequently helped with setting while Mother put the last touches on the roast. In the eating stage, family members shared the day's experiences and more than food was eaten. In this stage families got to know one another and made joint decisions around the dinner table, and thus the family unit was strengthened. In the cleaning-up stage, children or Father again gave their hands, so that their importance to the home community was clear. Unfortunately, all of these have been removed by a product---the television set.

By the beginning of the 1980s, the typical American family dinner was just twenty minutes long. The speed-up of the once-leisurely experiences is clearly connected to the pace of modern life and maybe a model of the modern life is the TV dinners --- meals designed to be eaten from the beginning to the end of a half-hour program. The once family affair has now become nothing more than the use of a fork and knife.

64. The underlined word in the second paragraph can be replaced by ____.

A. big             B. important             C. combined      D. separate

65. In the past, Americans tended to ____.

A. spend more time eating their food at dinner table

B. eat more food than they have today

C. spend more time talking about their day's experiences at dinner table

D. talk so much that they forgot to eat

66. The shortening of the dinner time in America is related to ____.

A. the TV programs                    B. the pace of modern life

C. the wide use of electrical equipment    D. the popularity of fast food

67. The best title for this passage might be ____.

A. Talk at Dinner Table                  B. TV Dinner

C. Pace of Modern Life                        D. Problems Caused by TV

判断题