Answer:
The pH value of the mixture will be 7.00
Explanation:
Mono and disodium hydrogen phosphate mixture act as a buffer to maintain pH value around 7. Henderson–Hasselbalch equation is used to determine the pH value of a buffer mixture, which is mathematically expressed as,
![pH=pK_{a} + log(\frac{[Base]}{[Acid]})](https://tex.z-dn.net/?f=pH%3DpK_%7Ba%7D%20%2B%20log%28%5Cfrac%7B%5BBase%5D%7D%7B%5BAcid%5D%7D%29)
According to the given conditions, the equation will become as follow
![pH=pK_{a} + log(\frac{[Na_{2}HPO_{4} ]}{[NaH_{2}PO_{4}]})](https://tex.z-dn.net/?f=pH%3DpK_%7Ba%7D%20%2B%20log%28%5Cfrac%7B%5BNa_%7B2%7DHPO_%7B4%7D%20%5D%7D%7B%5BNaH_%7B2%7DPO_%7B4%7D%5D%7D%29)
The base and acid are assigned by observing the pKa values of both the compounds; smaller value means more acidic. NaH₂PO₄ has a pKa value of 6.86, while Na₂HPO₄ has a pKa value of 12.32 (not given, but it's a constant). Another more easy way is to the count the acidic hydrogen in the molecular formula; the compound with more acidic hydrogens will be assigned acidic and vice versa.
Placing all the given data we obtain,
write the equation for the reaction
that is 6 F2 +P4 =4 PF3
find the theoretical mass that is
let the theoretical yield be represented by y
theoretical yield = 78.1/100 = 120/y
y= 153.6 grams
find the number of moles of PF3
moles = mass/molar mass
= 153.6/87.97 =1.746 moles
by use of mole ratio between F2 :PF3 which is 6:4 the moles of F2 is therefore= 1.746 x 6/4 = 2.62 moles
mass = moles x molar mass
= 1.746 moles x38 g/mol = 99.6 grams
Electrons fill the electron orbitals (s, p, d, or f) starting from the lowest energy level going to the highest energy level.
I hope this helps. let me know if you need more information such as what the
Answer:
The sum of the coefficients in the balanced equation is 11
Explanation:
A reaction where an organic compound reacts with oxygen to produce carbon dioxide and water is called combustion.
The balance reaction of combustion for methanol is:
2CH₃OH (l) + 3O₂(g) → 2CO₂(g) + 4H₂O (g)
Coefficients from stoichiometry are 2, 3, 2 and 4
Sum = 2 + 3 + 2 + 4 = 11
