Answer:
Explanation:
You can convert the <em>density</em> into <em>atomic density</em> using the <em>atomic weight </em>and Avogadro's number
A dimensional analysis is very helpful:
Follow the chain: g cancels with g, mol cancels with mol; at the end, what remains is atoms/cm³, which is what you want.
Use that with your data:
Si -Atomic number -14 -1s2 2s2 2p6 3s2 3p2 - 4 valence electrons
<span>Not all solids melt when they are heated. Some may undergo chemical changes as a result of heating. For example paper burns rather than melts</span>
Answer:
4.23.
Explanation:
<em>∵ pH = - log[H⁺].</em>
<em>For weak acids:</em>
∵ [H⁺] = √(ka)(c).
∴ [H⁺] = √(3.5 × 10⁻⁸)(0.10 M) = 5.92 x 10⁻⁵.
∴ pH = - log[H⁺] = - log(5.92 x 10⁻⁵) = 4.2279 ≅ 4.23.
What you were given is the balanced chemical equation
