题干

下列各选项中所述的两个量,前者一定大于后者的是()

A:pH=10的NaOH和Na2CO3溶液中,水的电离程度

B:物质的量浓度相等的NH4NO3溶液和氨水中NH4+的物质的量浓度

C:将pH=3的盐酸和醋酸分别加水稀释成pH=5的溶液,所加水的量

D:相同温度下,10mL 0.1mol·L-1的醋酸和100mL 0.01mol·L-1的醋酸中H+物质的量

上一题 下一题 0.0难度 选择题 更新时间:2017-05-15 11:30:03

答案(点此获取答案解析)

B

同类题5

   Scientists are placing robotic dogs in the homes of lonely old people to test whether they can improve the quality of life for humans. Alan Beck, an expert(专家) in human-animal relationship, and Nancy Edwards, a professor of nursing, are leading the animal-assisted study on the effect of robotic dogs on old people’s depression (沮丧) , physical activity, and life satisfaction.
   In the study, the robot, called AIBO, is placed for six weeks in the houses of some old people who live alone. Before placing AIBO in the home, scientists will collect baseline data(数据) for six weeks. These old people will keep a diary to note their feelings and activity before and after AIBO. Then, the scientists will review the data to test if it has produced any changes in the life of its owner.“I talk to him all the time, and he responds to my voice,” says a seventy-year-old lady. “When I’m watching TV, he’ll stay in my arms until he wants down. He has his own mind.”
   The AIBOs respond to certain orders. The scientists say they have some advantages over live dogs, especially for old people. Often the elderly are disabled and cannot care for an animal by walking it or playing with it. A robotic dog removes exercise and feeding concerns.
“At the beginning, it was believed that no one would relate(与……相关) to the robotic dog, because it was metal and not furry.” Beck says. “Hopefully, down the road, these robotic pets could become a more-valuable health helper. They will record their masters' blood pressure, oxygen levels or heart rhythms(心律). AIBOs may even one day have games that can help stimulate(刺激) older people's minds.”