Answer:
Six C atoms (C₆); five H atoms (H₅); one N atom (N); no O atoms
Explanation:
The rule of 13 states that the formula of a compound is a multiple n of 13 (the molar mass of CH) plus a remainder r.
MF = CₙHₙ₊ᵣ
Y has a molecular mass of 91 u
91/13 =7r0
The formula can't be C₇H₇ because a hydrocarbon must have an even number of H atoms,
The odd mass and the odd number of H atoms make it reasonable to add an N atom and subtract CH₂ (CH₂ = 14):
C₇H₇ + N - CH₂ = C₆H₅N
Check:
6C = 6 × 12.000 = 72.000 u
5H = 5 ×   1.008 =   5.040
 1N =  1 × 14.003 =  <u>14.003    </u>
              TOTAL =   91.043 u
This is excellent agreement with the observed mass of 91.0425 u.
There are six  C atoms (C₆)
There are five H atoms (H₅)
There is    one N atom   (N)
There are no   O atoms.
 
        
             
        
        
        
Answer: crest I don’t really know how to explain it but yea it’s crest
 
        
                    
             
        
        
        
Answer:
The Bohr model of the atom explains the reactivity of all atoms.
 
        
             
        
        
        
The Great Oxidation Event (GOE), sometimes also called the Great Oxygenation Event, Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust,[2] or Oxygen Revolution, was a time period when the Earth's atmosphere and the shallow ocean first experienced a rise in oxygen, approximately 2.4 billion years ago (2.4 Ga) to 2.1–2.0 Ga during the Paleoproterozoic era.[3] Geological, isotopic, and chemical evidence suggests that biologically produced molecular oxygen (dioxygen, O2) started to accumulate in Earth's atmosphere and changed Earth's atmosphere from a weakly reducing atmosphere to an oxidizing atmosphere,[4] causing many existing species on Earth to die out.[5] The cyanobacteria producing the oxygen caused the event which enabled the subsequent development of multicellular forms.
        
             
        
        
        
the correct answer would be the sun