I would have to say the answer is a. True.
Answer : The pressure in the flask after reaction complete is, 2.4 atm
Explanation :
To calculate the pressure in the flask after reaction is complete we are using ideal gas equation.
where,
P = final pressure in the flask = ?
R = gas constant = 0.0821 L.atm/mol.K
T = temperature = 
V = volume = 4.0 L
= moles of 
= 0.20 mol
= moles of 
= 0.20 mol
Now put all the given values in the above expression, we get:
Thus, the pressure in the flask after reaction complete is, 2.4 atm
Answer:
C. naturally uncombined with other elements.
Explanation: Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air.
The answer is b) the highest occupied orbital is a “d”orbital.
Transition metals are metals where the highest energy electrons partially fill the d subshells. There are some elements with complete d subshells but on forming cations they have incomplete d subshells.
These transition metals have some properties that are different from the other metals .
The statement that is true about magnets is ''Similar poles of a magnet repel each other.''
<h3>What are the characteristics of magnet?</h3>
All magnets have both north and south poles. Opposite poles attract each other, whereas the similar poles repel each other. When you rub a piece of iron along a magnet, this force creates a magnetic field.
So we can conclude that The statement that is true about magnets is ''Similar poles of a magnet repel each other.''
Learn more about magnet here: brainly.com/question/14997726
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