Mass of aspirin = 0.025 g
Molar mass of C9H8O4 is 180.1583 g/mol
moles of aspirin = .025g / 180.1583 g/mol = 0.000138767 moles
volume solution = .250 L
molarity of the solution = 0.000138767 moles / .250L =5.551 x 10 ^-04 Moles / liter
for aspirin i = Vant'Hoff factor = 1 particle in solution
T = 25 + 273 =298 K
osmotic pressure = M x R x T x i =
5.551 x 10 ^-04 mole L -1 x 0.08206 L atm K−1 mol−1 x 298 K x 1 = 0.0136 atmospheres
Answer:
6 moles of Cl2
Explanation:
First, the equation has to be balanced, which makes it 4 FeCl3 + 3 O2 --> 2 Fe2O3 + 6 Cl2
Using this information, we can see that one mole of O2 will not be present in the reaction. Since four moles of FeCl3 are needed to react in the equation, which would produce six moles of Cl2, and only four moles of FeCl3 are present, six moles of Cl2 would be produced.
<u>36 ml of NaOh and</u><u> 464 ml</u><u> of </u><u>HCOOH</u><u> would be enough to form 500 ml of a buffer with the same pH as the buffer made with </u><u>benzoic acid </u><u>and NaOH.</u>
What is benzoic acid found in?
- Some natural sources of benzoic acid include: Fruits: Apricots, prunes, berries, cranberries, peaches, kiwi, bananas, watermelon, pineapple, oranges.
- Spices: Cinnamon, cloves, allspice, cayenne pepper, mustard seeds, thyme, turmeric, coriander.
Calculate the amount of moles in NaOH and benzoic acid. This calculation is done by multiplying molarity by volume.
Amount of moles of NaOH -2 × 0.025 = 0.05 mol
Amount of moles of benzoic acid 2 × 0.475 = 0.095 mol
In this case, we can calculate the pH produced by the buffer of these two reagents, as follows
![pH = pKa + log\frac{base}{acid}](https://tex.z-dn.net/?f=pH%20%3D%20pKa%20%2B%20log%5Cfrac%7Bbase%7D%7Bacid%7D)
![4.2 + log\frac{0.05}{0.045} = 4.245](https://tex.z-dn.net/?f=4.2%20%2B%20log%5Cfrac%7B0.05%7D%7B0.045%7D%20%3D%204.245)
We must repeat this calculation, with the values shown for HCOOH and NaOH. In this case, we can calculate as follows
![pH = pKa + log\frac{base}{acid}](https://tex.z-dn.net/?f=pH%20%3D%20pKa%20%2B%20log%5Cfrac%7Bbase%7D%7Bacid%7D)
![4.245 = 3.75 + log\frac{base}{acid}](https://tex.z-dn.net/?f=4.245%20%3D%203.75%20%2B%20log%5Cfrac%7Bbase%7D%7Bacid%7D)
![log\frac{base}{acid} = 0.5](https://tex.z-dn.net/?f=log%5Cfrac%7Bbase%7D%7Bacid%7D%20%3D%200.5)
![\frac{base}{acid} = 3.162](https://tex.z-dn.net/?f=%5Cfrac%7Bbase%7D%7Bacid%7D%20%3D%203.162)
Now we must solve the equation above. This will be done using the following values
![\frac{2(0.5 - x)}{0.2x - 2(0.5 - x)} = 0.464 L](https://tex.z-dn.net/?f=%5Cfrac%7B2%280.5%20-%20x%29%7D%7B0.2x%20-%202%280.5%20-%20x%29%7D%20%3D%200.464%20L)
With these values, we can calculate the volumes of NaOH and HCOOH needed to make the buffer.
NaOH volume
( 0.5 - 0.464)L
0.036L .................... 36ml
HCOOH volume
500 - 36 = 464mL
Learn more about benzoic acid
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Answer:
Element symbol: Kr.
Mass number: 77.
Charge : 0.
Explanation:
Hello,
In this case, since such substance has the same amount of protons and electrons we can infer it is an atom whose number of neutrons is defined by considering its atomic mass or mass number and atomic number which is actually equal to the number of protons and electrons (36):
![neutrons=atomic\ mass - atomic\ number](https://tex.z-dn.net/?f=neutrons%3Datomic%5C%20mass%20-%20atomic%5C%20number)
In such a way, solving for the atomic mass we obtain:
![atomic\ mass=neutrons+ atomic\ number\\\\atomic\ mass=41+36=77](https://tex.z-dn.net/?f=atomic%5C%20mass%3Dneutrons%2B%20atomic%5C%20number%5C%5C%5C%5Catomic%5C%20mass%3D41%2B36%3D77)
It means that the element is krypton (Kr) as it has 36 electrons and protons so its charge is 0.
Best regards.