题干

商品生产者如果率先改进技术设备,提高劳动生产率,在同一时间内生产的(    )

A:单位商品价值量增加,商品价值总量增加,交换中获利可能增大

B:单位商品价值量增加,商品价值总量不变,交换中获利可能增大

C:单位商品价值量不变,商品价值总量增加,交换中获利可能增大

D:单位商品价值量降低,商品价值总量增加,交换中获利可能增大

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答案(点此获取答案解析)

C

同类题3

碳、氮、硫是中学化学重要的非金属元素,在工农业生产中有广泛的应用.

(1)用于发射“天宫一号”的长征二号火箭的燃料是液态偏二甲肼(CH32N﹣NH2,氧化剂是液态四氧化二氮.二者在反应过程中放出大量能量,同时生成无毒、无污染的气体.已知室温下,1g燃料完全燃烧释放出的能量为42.5kJ,请写出该反应的热化学方程式____ 

(2)298K时,在2L的密闭容器中,发生可逆反应2NO2(g)⇌N2O4(g)△H=﹣a kJ•mol﹣1 (a>0).N2O4的物质的量浓度随时间变化如图1.达平衡时,N2O4的浓度为NO2的2倍,回答下列问题.

①298k时,该反应的平衡常数为____ 

②在温度为T1、T2时,平衡体系中NO2的体积分数随压强变化曲线如图2所示.下列说法正确的是____ 

a.A、C两点的反应速率:A>C         

b.B、C两点的气体的平均相对分子质量:B<C

c.A、C两点气体的颜色:A深,C浅     

d.由状态B到状态A,可以用加热的方法

③若反应在398K进行,某时刻测得n(NO2)=0.6mol n(N2O4)=1.2mol,则此时V(正)____ V(逆)(填“>”、“<”或“=”).

(3)NH4HSO4在分析试剂、医药、电子工业中用途广泛.现向100mL 0.1mol•L﹣1NH4HSO4溶液中滴加0.1mol•L﹣1NaOH溶液,得到的溶液pH与NaOH溶液体积的关系曲线如图3所示.试分析图中a、b、c、d、e五个点,

①水的电离程度最大的是____ 

②其溶液中c(OH)的数值最接近NH3•H2O的电离常数K数值的是____ 

③在c点,溶液中各离子浓度由大到小的排列顺序是____ 

同类题4

    Whenever the house gets quiet, Mrs. Smith knows just where to find her 6-year-old daughter Maria: lost in the world of stories.“I like to read every time of the day,” said Maria, a student at Creel Elementary School in Australia.
    Maria's headmaster, Mrs. White, wants each of her 850 students and their families to learn the love of reading this year. She wants reading at home to become an activity of choice in every family, even during holiday breaks. "I truly realize reading should be an important part of everyone’s life, and nothing should stop it." said Mrs. White.
   “The aim we want most of all is to help children understand they can enjoy reading, as well as practice their skills,” said Hannas, an education researcher. He suggested parents take their children to the library and allow them to pick out books that interest them.
    Each night, students take home two books to read with their parents or other family members. They have to return the books the next day with a signed note from their parents showing that the books were read, and have passing tests that check how well they understand the books.
   “We're trying to get parents into the habit of reading with their kids.” said the headmaster. “Nothing is better than sitting on a sofa with your child and reading and laughing.”
    Through books, Mrs. Smith, a parent, said she's able to give her two daughters more experiences than she could.“I think reading opens all the doors and creates imaginations in children,”she said, “I think if you read well, you can succeed in anything in life.”