<span>The benefit of the space shuttle is that A. it's reusable. This means that after this shuttle has been used for one mission, it can be use for numerous other missions again, until it gets broken and cannot run anymore. B is incorrect because it cannot land - it is only there to observe. C is incorrect because more than one person can fit. D is incorrect because it doesn't orbit the Earth permanently - it returns at one point.</span>
Answer:
pH = 5.17
Explanation:
pH = -log[H+] = -log(6.7 x 10^-6) = 5.17
Answer:
Charge on Phosphate is -3 (PO₄³⁻)
Explanation:
Ions or polyatomic ions are formed when an atom or molecule loses or gains electron(s) respectively.
Example:
Formation of ions.
Na → Na⁺ + e⁻ (Na loses one electron)
Cl₂ + 2 e⁻ → 2 Cl⁻ (Cl gains electron)
In polyatomic ions a charge is present on a molecule which has either two or more atoms.
Example:
CO₃²⁻ , SO₄⁻ , NH₄⁺ e.t.c.
In statement the K₃PO₄ polyatomic ionic compound. It is made up of three K⁺ ions and one Phosphate ion (PO₄ˣ⁻) ion.
As we know K belongs to group 1 metals so it has one valence electron and thus, forms a cation of +1 charge. So, for a neutral polyatomic ionic compound the overall charge on K₃PO₄ should be zero. Hence,
K (3) + PO₄ (X) = 0
Or,
+3 + X = 0
Or,
X = 0 - 3
X = -3
Therefore, the charge on phosphate is -3.
Freezing point depression, ΔT, is calculated using the
formula:
ΔT= - Kf * molal
Where molal is the molality of the solute (moles solute/kg solvent)
In this case the solute is Barium Chloride while the solvent
is Water. The formula for molality is:
molal = (mass of solute / molar mass solute) / (mass of solvent)
molal = (116.8 g / 208.23 g/mol) / (0.25 kg Water) =
molal= 2.24 mol/kg = 2.24 m
Substituting to the 1st equation:
ΔT= - 1.86 °C/m
(2.24 m)
ΔT=
-4.17 °C
So the answer is A.