【单选题】Rubidium has two naturally occurring isotopes: 85Rb (atomic mass = 84.9118 amu) and 87Rb (atomic mass=86.9092 amu). The percent abundance of 87Rb can be estimated to be which of the following?
【单选题】The average atomic mass of 85 37 Rb(84.912 amu) and 87 37 Rb(86.909 amu) is 85.47amu,calculate the natrual abundance of the rubidium isotopes.
A.
85 Rb72.1% , 87 Rb 72.1%
B.
85 Rb 72.1%, 87 Rb 27.9%
C.
85 Rb 27.9% , 87 Rb 27.9%
【单选题】Atomic mass unit is a mass exactly equal to the mass of one atom.
【单选题】The atomic masses of its two stable isotopes 29 63 Cu(69.09 percent) and 29 65 Cu(30.91 percent) are 62.93 amu and 64.9278 amu, respectively.calculate the average atomic mass of copper.
【简答题】以下关于教育目的的论述,错误的选项是( )
【简答题】以下关于教育目的的论述,错误的选项是( )。
【单选题】16g X 2 O 5 contains 0.1 mol O , the relative atomic mass of X is
【单选题】某病人因齿龈出血来院检查,经化验血小板5.0×109/L,出血时间5分钟,红细胞计数4.0×1012/L,白细胞计数5.0×109/L,网织红细胞1%,应考虑为
【单选题】某病人因齿龈出血来院检查,经化验血小板0×109/L,出血时间5分钟,红细胞计数4.0×1012/L,白细胞计数5.0×109/L,网织红细胞1%,应考虑为
【单选题】Atomic mass is the mass of an atom in