Answer:
We are asked to describe the half-life of the radioactive materials.
- Hence the 3rd option is correct 
 
        
             
        
        
        
Answer:
                        1.66 × 10⁻¹⁸  Moles
Explanation:
                      As we know one mole of any substance contains 6.022 × 10²³ particles (atoms, ions, molecules or formula units). This number is also called as Avogadro's Number.
The relation between Moles, Number of Atoms and Avogadro's Number is given as,
              Number of Moles  =  Number of Atoms ÷ 6.022 × 10²³ Atoms/mol
Putting values,
               Number of Moles  =  1.0 × 10⁶ Atoms ÷ 6.022 × 10²³ Atoms/mol
               Number of Moles  =  1.66 × 10⁻¹⁸  Moles
 
        
             
        
        
        
Answer:
81.59%
Explanation:
First we <u>convert 107.50 g of NH₃ into moles</u>, using its <em>molar mass</em>:
- 107.50 g NH₃ ÷ 17 g/mol = 6.32 mol NH₃
Now we <u>calculate how many moles of NO would have been formed by the complete reaction of 6.32 moles of NH₃</u>:
- 6.32 mol NH₃ *  = 6.32 mol NO = 6.32 mol NO
Then we <u>convert 6.32 moles of NO to grams</u>, using its <em>molar mass</em>:
- 6.32 mol NO * 30 g/mol = 189.60 g NO
Finally we <u>calculate the percent yield</u>:
- 154.70 g / 189.60 g * 100% = 81.59%
 
        
             
        
        
        
Answer: 1.00×10^26=1000×10^23
1000×10^23/6.022×10^23=166.05×10^23 moles of water.
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Explanation:
 
        
             
        
        
        
Answer:
The reflection of sound waves
Explanation:
An echo is a reflection of sound that bounces of of one thing to another.