Answer:
ΔpH = 0.20
Explanation:
The buffer of HCO₃⁻ + CO₃²⁻ has a pka of 10.2
HCO₃⁻ ⇄ H⁺ + CO₃²⁻
There are 0.479moles of NaHCO₃ and 0.342moles of Na₂CO₃.
Using Henderson-Hasselbalch formula:
pH = pka + log [Base] / [Acid]
pH = 10.2 + log 0.342mol / 0.479mol
<em>pH = 10.05</em>
NaOH reacts with HCO₃⁻ producing CO₃²⁻, thus:
NaOH + HCO₃⁻ → CO₃²⁻ + H₂O + Na⁺
0.091 moles of NaOH produce the same moles of CO₃²⁻ and consume HCO₃⁻. Moles of these species are:
CO₃²⁻: 0.342mol + 0.091mol: 0.433mol
HCO₃⁻: 0.479mol - 0.091 mol: 0.388mol
Using Henderson-Hasselbalch formula:
pH = pka + log [Base] / [Acid]
pH = 10.2 + log 0.433mol / 0.388mol
pH = 10.25
That means change of pH, ΔpH is:
ΔpH = 10.25 - 10.05 = <em>0.20</em>
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I hope it helps!
It will slowly rotten and turn brown
Answer:
<h2> 162g/mol</h2>
Explanation:
The question is incomplete. The complete question includes the information to find the empirical formula of nicotine:
<em>Nicotine has the formula </em>
<em> . To determine its composition, a sample is burned in excess oxygen, producing the following results:</em>
<em>Assume that all the atoms in nicotine are present as products </em>
<h2>Solution</h2>
To find the empirical formula you need to find the moles of C, H, and N in each of the compound.
- 1.0 mol of CO₂ has 1.0 mol of C
- 0.70 mol of H₂O has 1.4 mol of H
- 0.20 mol of NO₂ has 0.20 mol of N
Thus, the ratio of moles is:
Divide all by the smallest number: 0.20
Hence, the empirical formula is C₅H₇N
Find the mass of 1 mole of units of the empirical formula:
Total mass = 60g + 7g + 14g = 81g
Two moles of units of the empirical formula weighs 2 × 81g = 162g and three units weighs 3 × 81g = 243 g.
Thus, since the molar mass is between 150 and 180 g/mol, the correct molar mass is 162g/mol and the molecular formula is twice the empirical formula: C₁₀H₁₄N₂.
Explanation:
It is known that 1 SCF produces approximately 1000 Btu of thermal energy.
As it is not mentioned for how many hours the gas is used in this process. Therefore, we assume that the total number of hours natural gas used in this process are as follows.
= 8760 hours
Now, we will calculate the annual cost of natural gas used in the process as follows.

= 555384000 SCF
Hence, annual cost of natural gas used in this process = loss of thermal energy
This will be equal to, 
= 555,384,000,000 BTU
Thus, we can conclude that the annual cost of natural gas used in the process is 555,384,000,000 BTU.