Answer:
21.5 g.
Explanation:
Hello!
In this case, since the reaction between the given compounds is:

We can see that according to the law of conservation of mass, which states that matter is neither created nor destroyed during a chemical reaction, the total mass of products equals the total mass of reactants based on the stoichiometric proportions; in such a way, we first need to compute the reacted moles of Li3P as shown below:

Now, the moles of Li3P consumed by 15 g of Al2O3:

Thus, we infer that just 0.29 moles of 0.73 react to form products; which means that the mass of formed products is:

Therefore, the total mass of products is:

Which is not the same to the reactants (53 g) because there is an excess of Li₃P.
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I would pick the first option in the third option
Answer:
Chlorine is more likely to steal a valence electron from sodium.
Explanation:
Sodium is number 11 on the periodic table with one valence electron. Belonging to the first group, it's one of the alkali metal, which are known to be highly reactive. Chlorine is number 17 with seven valence electrons, and it's in the second-to-last group of halogens--also very reactive.
Considering that elements with one valence electron are just about 100% likely to give up electrons to reach a stable state, sodium would be the element that is more likely to lose its valence electron to chlorine. In other words, chlorine would be the electron thief.