There is one calcium, one carbon atom, and three oxygen atoms. Therefore, there are 5 atoms in CaCo3
In order to understand what is the limiting reactant is useful to convert the masses of reactants into moles. The molecular masses are:

Converting masses into moles:


In the reaction, 2 moles of

are necessary to react with 1 mol of

. Following this ratio:

We have only 0.5 mol of

, i.e, we don't have enough amount of salicylic acid, therefore, this is the limiting reactant.
The indole test is a qualitative procedure for determining the ability of bacteria to produce indole by deamination of tryptophan. Using Kovacs tube method, indole combines, in the presence of a tryptophan rich medium, with p-Dimethylaminobenzaldehyde at an acid pH in alcohol to produce a red-violet compound.
Answer:
0.375 L
Explanation:
We know that at neutralization, the number of mol of acid must equal the number of equivalents of base.
This is a reaction 1:1 acid to base:
HClO₄ + NaOH ⇒ NaClO₄ + H₂O
We re given the moles of the base indirectly since we know the volume and molarity. From there we can calculate the volume of HClO₄.
Moles NaOH = 0.115 L x 0.244 M = 0.115 L x 0.244 mol/L =0.028 mol
Thus we require 0.028 mol of HClO₄ in the pechloric acid solution:
Molarity = # moles / V ⇒ V = # moles / M
V = 0.028 mol / 0.0748 mol/L = 0.375 L
Note that this problem can be solved in just one step since
M(HClO₄) x V(HClO₄) = M(NaOH) x V(NaOH) ⇒
V(HClO₄) = M(NaOH) x V(NaOH) / M(HClO₄)
It has ns1 electron configuration like the alkali metals.