Ban đầu có 10 g chất X24. Biết X phóng xạ β- thì sau 3 chu kì có bao nhiêu hạt β- tạo thành? Cho NA = 6,022.1023 hạt/mol.

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Một số câu hỏi khác có thể bạn quan tâm.

• Choose a word that has different stress pattern:

  tragedy                             effective                               history                      nursery

• Choose a word that has different stress pattern:

  robot                       upper                        surprise                         infant

• Choose the best answer for the following sentence:

  It’s time we concentrated on our _____________ business.
  
  
  

• Choose the best answer for the following sentence:

  ______________ mortality rates are associated with many factors, including maternal realth, access to medical care, socio-economic conditions and public health practices.
  

• Choose the best answer for the following sentence:

  Few of them have made much ____________ in those branches of industry which give a variety and complexity to the affairs of a nation.
   

• Choose the best answer for the following sentence:

  They are conducting a campaign to ___________ the public about the dangers of smoking.
   

• Choose the best answer for the following sentence:

  The stores are __________ specials on sweaters this weekend.
   

• Choose the best answer for the following sentence:

  Schools' systems may also lead them to report scholarships in the calendar year of the __________ term.
   

• Choose the best answer for the following sentence:

  The public knows little of him, but in the ____________ he's known as a fine mathematician.
   

• Choose the best answer for the following sentence:

  If you're the ____________ and everybody thinks you'll win, how does anybody be against you?