The coal industry has been targeted by its critics as a significant contributor to the greenhouse effect. However, the greenhouse effect is a natural phenomenon involving the increase in global surface temperature due to the presence of greenhouse gases—water vapor, carbon dioxide, methane and nitrous oxide--in the atmosphere. Without the greenhouse effect, the earth's average surface temperature would be 33-35℃ lower, or -15℃. Life on earth, as we know it today, would not be possible.
There is concern that this natural phenomenon is being altered by a greater build-up of gases from human activity, perhaps giving rise to additional warming and changes in the earth' s climate. This additional build-up and its forecast outcome has been called the enhanced greenhouse effect. Considerable uncertainty exists, however, about the enhanced greenhouse effect, particularly in relation to the extent and timing of any future increases in global temperature.
Greenhouse gases arise from a wide range of sources and their increasing concentration is largely related to the compound effects of increased population, improved living standards and changes in lifestyle. From a current base of 5 billion, the United Nations predicts that the global population may stabilize in the twenty-first century between 8 and 14 billion, with more than 90 percent of the projected increase taking place in the
world's developing nations. The associated activities to support that growth, particularly to produce the required energy and food, will cause further increases in greenhouse gas emissions. The challenge, therefore, is to attain a sustainable balance between population, economic growth and the environment.
The major greenhouse gas emissions from human activities are carbon dioxide (CO2), methane and njtrous oxide. Chlorofiuorocarbons (CFCs) are the only major contributor to the greenhouse effect that does not occur naturally, coming from such sources as refrigeration, plastics and manufacture. Coal's total contribution to greenhouse gas emissions is thought to be about 18 percent, with about half of this coming from electricity generation.
Effects have been made to guarantee the status of coal industry except ______.
A.analyzing coal's relation to the greenhouse effect
B.controlling pollution at modem mines
C.cutting down emissions of greenhouse gases
D.maintaining efficiencies during coal consumption
第1题
《生活饮用水标准检验法》中,采用下列哪个方法制备测酚用的纯水
A、加硫酸至酸性后进行蒸馏
B、加高锰酸钾及硫酸至酸性后进行蒸馏
C、加氢氧化钠至pH12以上进行蒸馏
D、加高锰酸钾及硝酸至酸性后进行蒸馏
E、加硝酸至酸性后进行蒸馏
第2题
测酚用的纯水,应为无酚纯水,《生活饮用水标准检验法》采用的下列哪种制备方法()。
A、加高锰酸钾及硝酸至酸性后进行蒸馏
B、加硫酸至酸性后进行蒸馏
C、加硝酸至酸性后进行蒸馏
D、加高锰酸钾及硫酸至酸性后进行蒸馏
E、加氢氧化钠至pH 12以上进行蒸馏
第3题
《生活饮用水标准检验法》采用下列哪种方法制备测酚用的纯水
A、加硫酸至酸性后进行蒸馏
B、加高锰酸钾及硫酸至酸性后进行蒸馏
C、加氢氧化钠至pH12以上进行蒸馏
D、加高锰酸钾及硝酸至酸性后进行蒸馏
E、加硝酸至酸性后进行蒸馏
第4题
测酚用的纯水,应为无酚纯水,《生活饮用水标准检验法》采用的制备方法是
A、加硫酸至酸性后进行蒸馏
B、加高锰酸钾及硫酸至酸性后进行蒸馏
C、加硝酸至酸性后进行蒸馏
D、加高锰酸钾及硝酸至酸性后进行蒸馏
E、加氢氧化钠至pH12以上进行蒸馏
第5题
《生活饮用水标准检验法》中,制备测酚用的纯水,采用
A、加硫酸至酸性后进行蒸馏
B、加高锰酸钾及硫酸至酸性后进行蒸馏
C、加氢氧化钠至pH12以上进行蒸馏
D、加高锰酸钾及硝酸至酸性后进行蒸馏
E、加硝酸至酸性后进行蒸馏
第6题
A.加高锰酸钾及硝酸至酸性后进行蒸馏
B.加硫酸至酸性后进行蒸馏
C.加硝酸至酸性后进行蒸馏
D.加高锰酸钾及硫酸至酸性后进行蒸馏
E.加氢氧化钠至p
F.12以上进行蒸馏
第7题
A.加硫酸至酸性后进行蒸馏
B.加高锰酸钾及硫酸至酸性后进行蒸馏
C.加硝酸至酸性后进行蒸馏
D.加硝酸至酸性后进行蒸馏
E.加氢氧化钠至pH12以上进行蒸馏
第8题
A.加硫酸至酸性后进行蒸馏
B.加高锰酸钾及硫酸至酸性后进行蒸馏
C.加硝酸至酸性后进行蒸馏
D.加高锰酸钾及硝酸至酸性后进行蒸馏
E.加氢氧化钠至p
F.12以上进行蒸馏
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