Answer: Number of molecules of hydrogen gas 
Explanation:
Number of moles of sodium =
According to reaction , 2 moles of sodium produces 1 mole of hydrogen gas , then 2.11 mol of sodium will= 
of hydrogen gas that is 1.05 moles of hydrogen gas.
Number of molecules = 
moles of substance
Moles of hydrogen gas formed = 1.05 moles
Number of molecules of hydrogen gas = 
moles of hydrogen gas
Number of molecules of hydrogen gas 
Answer:
phosphorus - least similar to barium
beryllium - most similar to barium
Explanation:
The formula of the chloride formed between barium and chlorine is BaCl2.
Barium is a metallic element and has the valency of +2. Beryllium is also a group two metal with a valency of +2. Hence the compound formed between beryllium and chlorine is BeCl2
Phosphorus is a nonmetal and forms a completely different chloride from BaCl2. The chloride of phosphorus is PCl5 and PCl3. These are least similar to BaCl2
Explanation:
A reaction quotient is defined as the ratio of concentration of products over reactants raised to the power of their stoichiometric coefficients.
A reaction quotient is denoted by the symbol Q.
For example, 
The reaction quotient for this reaction is as follows.
Q = ![\frac{[Fe^{2+}]^{2}[Zn^{2+}]}{[Fe^{3+}]^{2}}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BFe%5E%7B2%2B%7D%5D%5E%7B2%7D%5BZn%5E%7B2%2B%7D%5D%7D%7B%5BFe%5E%7B3%2B%7D%5D%5E%7B2%7D%7D)
[Zn] will be equal to 1 as it is present in solid state. Therefore, we don't need to write it in the reaction quotient expression.
