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:
Choice number two: this element is malleable and ductile.
Explanation:
A modern periodic table can be split into three sections:
(from left to right)
Based on the descriptions, section A likely refers to the metals. Section B likely refers to metalloids. Section C likely refers to nonmetals.
Metals are malleable and ductile. They are good conductors of electricity.
The reason is that in a metal, the valence electrons do not belong to some specific atom. Rather, the metal cations share these electrons. The electrons are free to move around the metal and conduct electricity.
Ionic compounds like table salt are brittle. The reason is that when an ionic compound is deshaped, ions of the same charge come directly into contact with each other. That creates repulsion and cracks the crystal. In contrast, the metal cations in a metal won't come into contact with each other. Electrons would rapidly fill the gap between these cations, so the metal won't crack. That's why unlike ionic compounds, metals are malleable and ductile.
The melting points of metals can vary significantly. Indeed, the mercury (, a metal) is a liquid at room temperature. In contrast, tungsten (
, also a metal) won't melt until it is heated to over
.