Answer:
Superscript 6 Subscript 2 Baseline Upper H e right arrow Superscript 6 Subscript 3 Baseline Upper L i + Superscript 0 Subscript negative 1 Baseline e
Explanation:
Helium decays by beta emission, in beta emission, the mass number of the parent and daughter nuclei are the same but the atomic number of the daughter nucleus increases by one hence it is found one place to the right of its parent in the periodic table.
Having said this, the decay of Helium to lithium may be written as follows;
6/2He -> 6/3Li + 0/-1e
Atmospheric oxygen DID increase after the evolution of photosynthetic prokaryotes. So It is true.
Steel wool rusts faster because more Surface Area is exposed in a steel wool compared to the iron nail and more surface area means faster rusting rates
have a nice day! (^o^)
Answer:
B) 8.0 molecules.
Explanation:
- From the balanced equation: <em>3Cu + 8HNO₃ → 3Cu(NO₃)₂ + 2NO + 4H₂O,</em>
It is clear that 3.0 atoms of Cu react with 8.0 molecules of HNO₃ to produce 3.0 molecules of Cu(NO₃)₂, 2.0 molecules of NO, and 4.0 atoms of H₂O.
<u><em>Note that: </em></u>The no. of atoms and molecules is the same ratio to the no. of moles.
<u><em>Using cross multiplication:</em></u>
3.0 atoms of Cu produce → 2.0 molecules of NO, from the balanced equation.
12.0 atoms of Cu produce → <em>??? molecules of NO.</em>
<em>∴ The no. of molecules of NO produced </em>= (2.0 molecules)(12.0 atoms)/(3.0 atoms) = <em>8.0 molecules.</em>
