Answer:
In the Lewis structure of P4 there are 6 bonding pairs and 4 lone pairs of electrons.
Explanation:
The structure of tetrahedral molecule of P4 is provided below.
Each phosphorus atom has 5 valence electrons out of which 3 electrons involve in bonding and the rest 2 electrons exist as a lone pair that does not involve in bonding.Hence each phosphorus atom has one lone pair.In P4 molecule there are phosphorus atoms and hence 4 lone pairs in total.
As you can see in the figure, each phosphorus atom is bonded to the other three atoms.A bond is formed when two atoms share one electron each and the pair is called bonding pair.
From the figure we can see that there are 6 bonds in total.Each bond consist of one bonding pair of electrons and hence in total there are 6 bonding pairs of electrons.
Hence in a P4 molecule there are six bonding pairs and 4 lone pairs of electrons.
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,
Solve these problems like weighted averages:
The first one:
Multiply the masses (isotope numbers) by the decimal form of the percentage. Add them
0.076 (6) + 0.924 (7) = 6.924
The second one:
0.2 (10) + 0.8 (11) = 10.8
If you think about it, these answers make sense. 6.924 is much closer to 7 than to 6 (since there's a lot more lithium-7 than there is lithium-6). 10.8 is closer to 11 than to 10.
Location = nucleus ,
and you can see the total charge on the number that written below the substance, which would be 28+
hope this helps
If 30 grams of KCl is dissolved at 10°C, 14 g of KCl should be added to make a saturated solution at 60 °C.
<h3>What is a saturated solution?</h3>
A saturated solution is a solution in which there is so much solute that if there was any more, it would not dissolve. Its concentration is the same as the solubility at that temperature.
- Step 1. Calculate the mass of water.
At 10 °C, the solubility is 31.2 g KCl/100 g H₂O.
30 g KCl × 100 g H₂O/31.2 g KCl = 96 g H₂O
- Step 2. Calculate the mass of KCl required to prepare a saturated solution at 60 °C.
At 60 °C, the solubility is 45.8 g KCl/100 g H₂O.
96 g H₂O × 45.8 g KCl/100 g H₂O = 44 g KCl
- Step 3. Calculate the mass of KCl that must be added.
44 g - 30 g = 14 g
If 30 grams of KCl is dissolved at 10°C, 14 g of KCl should be added to make a saturated solution at 60 °C.
Learn more about saturated solutions here: brainly.com/question/24564260
