During the experiment, scientists noted that several of the reaction beakers became hot to the touch. All of the following reactions could cause this result except endothermic and positive ∆H experiments.
<u>Explanation:</u>
If the beakers are becoming hot during experimentation, then that means the energy is being released from the reactants during this experiment. As the energy is being released that enthalpy change will also be negative as the enthalpy change is calculated as the difference of enthalpy of reactants from products.
So in these cases, heat is released making the beakers hot. So for the exceptional case, the experiment should be endothermic in nature and positive enthalpy change should be there in the experiment. Such that the heat will not be released leading to no heating of beakers.
Answer:
Fe(NO2)3
Explanation:
A poly atomic ion is an ion that contains more than one atom.
If we look at all the compounds that have been mentioned among the options; KBr and NaF are both ionic but do not contain any covalent poly atomic ion.
However, Fe(NO2)3 contains NO2^+ which is a poly atomic ion that contains the covalent bond.
The answer is foramen, which means opening.
This is term used in anatomy.
Its plural is foramina.
The foramina tipically allow the connection of two parts of the body through bloed vessels (arteries, veins) or nerves.
