Answer:
The answer is: the body contains chemicals called buffers that resist changes in pH
When you exercise vigorously, the muscle will produce more carbon dioxide which will makes the blood more acidic. Human blood have some mechanism that could prevent the blood pH to stray further from the optimal range. One of the buffer that keep carbon dioxide acidity would be sodium bicarbonate.
Explanation:
<h2>
it just be like that sometimes my dude</h2>
<span>Earth has a much greater mass than Pluto does, and therefore has stronger gravity.</span>
Acid is anything which will give H+ to other species.
Have a look at the equations given.
In A) HCl changes to Cl- by giving its H+ to H2O. So HCl is an acid.
In B) HCO3- changes to H2CO3^2- by accepting H+. It did Not give its H+ rather it takes from other species. So it is not an acid at all.
In C) H2O is just breaking to H+ and OH-. It is not giving H+ to other species. So it is also not an acid in this reaction.
In D) HCOOH is giving its H+ to H2O. So it is also an acid.
So out of all reactions with water. The only two species are acting as acid with water namely HCl and HCOOH.
Out of these two HCl is very strong acid but HCOOH is a weak acid.
So the answer is D
<u>Answer:</u>
The correct answer option is C. 2.
<u>Explanation:</u>
We are given the number '0.0020' and we are to indicate the number of significant figures in the given measured number.
According to the rules of significant figures, numbers that are non-zero, zeros between any two significant numbers and the ending zeros in the decimal position are categorized as significant figures.
Since there is one non-zero number and one ending zero in the decimal position, therefore 0.0020 has 2 significant figures.
For this problem, we use the Hess' Law.
ΔHrxn = ∑(ν*Hf of products) - ∑(ν*Hf of reactants)
The ν represents the corresponding stoichiometric coefficients of the substances, while Hf is the heat of formation. For pure elements, Hf = 0.
Hf of Al₂O₃ = <span>−1676.4 kJ/mol
</span>Hf of Fe₂O₃ = <span>-826.0 kJ/mol
Thus,
</span>ΔHrxn = 1*−1676.4 kJ/mol + 1*-826.0 kJ/mol
<em>ΔHrxn = -2502.4 kJ/mol</em>
