Number #2 is joule
In the SI system the unit of heat is the joule. The calorie was defined so that the heat capacity of water was equal to one.The heat capacity of a substance is the amount of heat required to raise the temperature of a defined amount of pure substances by one degree.
Number #3 is Endothermic
Why? I can't explain. I Just left class where they were just explaining that.
Answer:
Back titration is a titration done in reverse; instead of titrating the original sample, a known excess of standard reagent is added to the solution, and the excess is titrated.
I hope it's helpful!
I will use [pV/T] in the state 1 = [pV/T] in the state 2.
State 1:
p = 1.0 atm
V = 25 liter
T = 100 + 273.15 = 373.15 K
State 2:
p = 19.71 mmHg * 1.atm / 760 mmHg = 0.0259atm
V= ?
T = 25 + 273.15 = 298.15 K
Application of the formula
1.0 atm * 25 liter / 373.15 k = 0.0259 atm * V / 298.15 K =>
V = [1.0atm * 25 liter / 373.15 K]*298.15K/0.0259atm = 771 liter
Answer:
Tetrahedral, trigonal pyramidal, trigonal bipyramidal.
Explanation:
The VSPER theory states that the bonds of sharing electrons and the lone pairs of electrons will repulse as much as possible. So, by the repulsion, the molecule will have some shape.
In the ion PO₄³⁻, the central atom P has 5 electrons in its valence shell, so it needs 3 electrons to be stable. Oxygen has 6 electrons at the valence shell and needs 2 to be stable. 3 oxygens share 1 pair of electrons with P, and the two lone pair remaining in P is shared with the other O, then the central atom makes 4 bonds and has no lone pairs, the shape is tetrahedral.
In the ion H₃O⁺, the central atom O has 6 electrons in its valence shell and needs 2 electrons to be stable. The hydrogen has 1 electron, and need 1 more to be stable. The hydrogens share 1 pair of electrons with the oxygen, then it remains 3 electrons at the central atom, and the VSPER theory states that the shape will be a trigonal pyramidal.
In the AsF₅, the central atom As has 5 valence electrons, and F has 1 electron in its valence shell, so each F shares one pair of electrons with As, and there are no lone pairs in the central atom. For 5 bonds without lone pairs, the shape is trigonal bipyramidal.
1st level = s
<span>2nd level = s,p </span>
<span>3rd level = s,p,d </span>
<span>4th level = s,p,d,f</span>
