Answer:
Kc = 105062.5 at 298K
Explanation:
First of all, we state the equilibrium:
3O₂(g) ⇄ 2O₃(g)
We know data about equilibrium concentration of oxygen. We suppose 1 mol of oxygen at the begining. During the reaction, x moles have reacted.
As ratio is 2:3, we can determine how many moles of ozone have been produced.
(x . 2)/3
So we have the final concentration of oxygen, so, let's find out x
1 - x = 0.016 moles
x = 0.984 moles
Then, the [O₃] in equilibrium will be (0.984 . 2) /3 = 0.656.
We supose a volume of 1 L, so we have molar concentration to determine Kc. Let's state the expression for it:
Kc = [O₃]² / [O₂]³
Kc = 0.656² / 0.016³ → 105062.5
Answer:
![\boxed {\boxed {\sf A. \ 2.48 \ mol \ Na_2O}}](https://tex.z-dn.net/?f=%5Cboxed%20%7B%5Cboxed%20%7B%5Csf%20A.%20%5C%202.48%20%5C%20mol%20%5C%20Na_2O%7D%7D)
Explanation:
We are asked to convert an amount in grams to moles. To do this, we use the molar mass. This is the number of grams in one mole of a substance. It is the same value numerically as the atomic mass on the Periodic Table, however the units are grams per mole, not atomic mass units.
Look up the molar masses for the individual elements.
- Sodium (Na): 22.9897693 g/mol
- Oxygen (O): 15.999 g/mol
Look back at the formula: Na₂O. Notice there is a subscript of 2 after sodium. This means there are 2 atoms of sodium in every molecule, so we have to multiply sodium's molar mass by 2 before adding oxygen's.
- Na₂O: 2(22.9897693 g/mol)+ 15.999 g/mol = 61.9785386 g/mol
Set up a ratio using the molar mass.
![\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}](https://tex.z-dn.net/?f=%5Cfrac%20%7B61.9785386%20%5C%20g%20%5C%20Na_2O%7D%7B1%20%5C%20mol%20%5C%20Na_2O%7D)
Multiply by the given number of grams.
![154 \ g \ Na_2O*\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}](https://tex.z-dn.net/?f=154%20%5C%20g%20%5C%20Na_2O%2A%5Cfrac%20%7B61.9785386%20%5C%20g%20%5C%20Na_2O%7D%7B1%20%5C%20mol%20%5C%20Na_2O%7D)
Flip the ratio so the grams of sodium oxide can cancel each other out.
![154 \ g \ Na_2O*\frac {1 \ mol \ Na_2O}{61.9785386 \ g \ Na_2O}](https://tex.z-dn.net/?f=154%20%5C%20g%20%5C%20Na_2O%2A%5Cfrac%20%7B1%20%20%5C%20mol%20%5C%20Na_2O%7D%7B61.9785386%20%5C%20g%20%5C%20Na_2O%7D)
![154 *\frac {1 \ mol \ Na_2O}{61.9785386 }](https://tex.z-dn.net/?f=154%20%2A%5Cfrac%20%7B1%20%20%5C%20mol%20%5C%20Na_2O%7D%7B61.9785386%20%7D)
![\frac {154}{61.9785386 } \ mol \ Na_2O](https://tex.z-dn.net/?f=%5Cfrac%20%7B154%7D%7B61.9785386%20%7D%20%20%5C%20mol%20%5C%20Na_2O)
![2.48473106141 \ mol \ Na_2O](https://tex.z-dn.net/?f=2.48473106141%20%5C%20mol%20%5C%20Na_2O)
The original measurement of grams given has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.
The 4 in the thousandth place tells us to leave the 8.
![2.48 \ mol \ Na_2O](https://tex.z-dn.net/?f=2.48%20%5C%20mol%20%5C%20Na_2O)
There are <u>2.48 moles of sodium oxide</u> in 154 grams, so choice A is correct.
Answer:
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Answer:In the solid state, ionic compounds such as sodium chloride have their ions fixed in position and therefore these ions cannot move so solid ionic compounds cannot conduct electricity. However in the molten state, ions in ionic compounds are free to flow and therefore molten sodium chloride can conduct electricity.
Explanation: