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>
Answer:
6.5x10⁻³M = [OH⁻]
Explanation:
The Kb of a Weak base as ethylamine is expressed as follows:
Kb = [OH⁻] [C₂H₅NH₃⁺] / [C₂H₅NH₂]
As the equilibrium of ethylenamine is:
C₂H₅NH₂(aq) + H₂O(l) ⇄ C₂H₅NH₃⁺(aq) + OH(aq)
The concentration of C₂H₅NH₃⁺(aq) + OH(aq) is the same because both ions comes from the same equilibrium. Thus, we can write:
Kb = [OH⁻] [C₂H₅NH₃⁺] / [C₂H₅NH₂]
6.4x10⁻⁴ = [X] [X] / [C₂H₅NH₂]
Also, we can assume the concentration of ethylamine doesn't decrease. Replacing:
6.4x10⁻⁴ = [X] [X] / [0.066M]
4.224x10⁻⁵ = X²
6.5x10⁻³M = X
<h3>6.5x10⁻³M = [OH⁻]</h3>
four covalent bonds in SiO2
Answer:
12.66 L
Explanation:
- Used combined gas law formula
- Change C to K
- Rearrange formula to fit your values
- If you would like further explanation or want to learn how to do these please let me know. Hope this helped!
Because it has less surface area. This can be applied to something like cooking potatoes. Cooking a larger potato will take longer than a small potato.
