D. all of the above, although I do find it hard to believe something like flour would have a melting point, I looked up my answer to double check.
Answer:
Determine the pH of the solution half-way to the end-point on the pH titration curve for acetic acid.
Explanation:
The equation for the ionization of acetic acid is
HA + H₂O ⇌ H₃O⁺ + A⁻
For points between the starting and equivalence points, the pH is given by the Henderson-Hasselbalch equation:
![\text{pH} = \text{pK}_{\text{a}} + \log\dfrac{[\text{A}^{-}]}{\text{[HA]}}](https://tex.z-dn.net/?f=%5Ctext%7BpH%7D%20%3D%20%5Ctext%7BpK%7D_%7B%5Ctext%7Ba%7D%7D%20%2B%20%5Clog%5Cdfrac%7B%5B%5Ctext%7BA%7D%5E%7B-%7D%5D%7D%7B%5Ctext%7B%5BHA%5D%7D%7D)
At the half-way point, half of the HA has been converted to A⁻, so [HA] = [A⁻]. Then,
The pKₐ is the pH at the half-way point in the titration.
Answer:
1.82x10⁻¹⁹Joules is the energy of the photon that is absorbed by the electron.
Explanation:
The energy of a photon is given by the equation:
E = h×ν
<em>Where E is energy of the photon in Joules.</em>
<em>h is Planck's constant (6.6262x10⁻³⁴Js)</em>
<em>And ν is frequency of the photon (In Hz = s⁻¹)</em>
<em />
The frequency of the photon is 2.74x10¹⁴Hz. That means its energy is:
E = 6.6262x10⁻³⁴Js × 2.74x10¹⁴s⁻¹
E =
<h3>1.82x10⁻¹⁹Joules is the energy of the photon that is absorbed by the electron</h3>
<em />
The question has missing information, the complete question is:
Cobalt(II) chloride forms several hydrates with the general formula CoCl₂.xH₂O, where x is an integer. If the hydrate is heated, the water can be driven off, leaving pure CoCl₂ behind. Suppose a sample of a certain hydrate is heated until all the water is removed, and it's found that the mass of the sample decreases by 22.0%. Which hydrate is it? That is, what is x?
Answer:
CoCl₂.26H₂O
Explanation:
The molar masses of the compounds that forms the hydrate are:
Co = 59 g/mol
Cl = 35.5 g/mol
H = 1 g/mol
O = 16 g/mol
The molar mass of CoCl₂ is 130 g/mol and of H₂O is 18 g/mol, thus for the hydrate, it will be 130 + 18x g/mol.
Let's suppose 1 mol of the compound. Thus, the mass of the hydrate is: 130 + 18x, and the mass of CoCl₂ will be 130 g. Because the mass decreassed by 22.0% :
0.22*(130 + 18x) = 130
130 + 18x = 590.91
18x = 460.91
x ≅ 26
Thus, the hydrate is CoCl₂.26H₂O
Answer:
The complete question is as follows
Given the incomplete equation: 2 N2O5(g) ==> Which set of products completes and balances the incomplete equation?
A)2 N2(g) + 3 H2(g)
B)2 N2(g) + 2 O2(g)
C)4 NO2(g) + O2(g)
D)4 NO(g) + SO2(g)
The correct option is C) 4NO2(g) + O2(g)
Explanation:
Note that the products should be NO2 and O2 since the reactant is entirely made up of N and O. option A is not correct as hydrogen cannot emerge as a product in this reaction. Matter can never be created or be destroyed bu can only change in a chemical reaction. Option D is not also correct for the same reason.
Option B is not correct since it did not balance the number of atoms of O and N in the reactant side of the equation.
The option C) 4NO2(g) + O2(g) is therefore the right option since it balances both the elements and the number of atoms of the elements present.
