Answer:
The pH of the buffer solution = 8.05
Explanation:
Using the Henderson - Hasselbalch equation;
pH = pKa₂ + log ( [HPO₄²-]/[H₂PO4⁻]
where pKa₂ = -log (Ka₂) = -log ( 6.1 * 10⁻⁸) = 7.21
Concentration of OH⁻ added = 0.069 M (i.e. 0.069 mol/L)
[H₂PO4⁻] after addition of OH⁻ = 0.165 - 0.069 = 0.096 M
[HPO₄²-] after addition of OH⁻ = 0.594 + 0.069 = 0.663 M
Therefore,
pH = 7.21 + log (0.663 / 0.096)
pH = 7.21 + 0.84
pH = 8.05
Answer:
3.67 moles of N
Explanation:
The epinephrine's chemical formula is: C₉H₁₃O₃N
We were told that a chemist found that in a mesaure of epinephrine, he found 33 moles of C
We must know that 9 moles of C are in 1 mol of C₉H₁₃O₃N so, let's make a rule of three:
If 9 moles of C are found in 1 mol of C₉H₁₃O₃N
Therefore 33 moles of C must be found in (33 .1) / 9 = 3.67 moles of C₉H₁₃O₃N
There is a second rule of three, then.
In 1 mol of C₉H₁₃O₃N we have 1 mol of N
Then, 3.67 moles C₉H₁₃O₃N must have (3.67 . 1) / 1 = 3.67 moles of N
Remember 1 mol of C₉H₁₃O₃N has 9 moles of C, 13 moles of H, 3 moles of O and 1 mol of N
Answer: Order of the elements from most reactive to least reactive is:
Mg > Zn > Fe > H > Cu
Explanation: Reactivity of the elements is the tendency of the elements to loose or gain electrons with ease.
As, all the given elements are metals, so the metals which will loose electrons easily will be more reactive. To study the reactivity of metals, we use reactivity series.
The metals which are more reactive are placed on the top of the reactivity series and which are less reactive are placed at the bottom.
Hence, the order of the elements from most reactive to least reactive is:
Mg > Zn > Fe > H > Cu
Reactivity series is attached below.
Answer:
to determine of it is a solid liquid or gas.
Explanation:
The melting point is the temperature at which a substance converts from a solid state to a liquid state.
