7.0 this is the correct answer
Answer:
Explanation:
<u>1) Chemical equation (given)</u>
<u>2) Theoretical yield</u>
<u>a) Convert mass of NaHCO₃ to moles:</u>
- n = mass in grams / molar mass
- molar mass = 84.007 g/mol
- n = 2.36 g / 84.007 g/mol = 0.02809 mol
<u>b) Mole ratio:</u>
- 2 mol NaHCO₃ : 1 mol H₂CO₃
<u>c) Proportionality:</u>
- 2 mol NaHCO₃ / mol H₂CO₃ = 0.02809 mol NaHCO₃ / x
⇒ x = 0.2809 / 2 mol H₂CO₃ = 0.01405 mol H₂CO₃
<u>3) Actual yield</u>
<u>a) Mass balance</u>: 2.36 g - 1.57 g = 0.79 g
<u>b) Convert 0.79 g of carbonic acid to number of moles</u>:
- n = mass in grams / molar mass
- n = 0.79 g / 62.03 g/mol = 0.01274 mol
<u>4) Percentage yield, y (%)</u>
- y (%) = actual yield / theoretical yield × 100
- y (%) = 0.1274 mol / 0.1405 mol × 100 = 90.68%
The answer must show 3 significant figures, so y(%) = 90.7%.
Answer:
- Please, find the drawing in the picture attached.
Explanation:
A simple model or drawing of the structure of an atom may be performed showing the electrons on the different energy levels (shells), plus the nucleons (protons and neutrons).
Then, you need the information on:
- number of protons (atomic number)
- electron configuration
- number of neutrons
The first step is to find the atomic number of the atom. You find that information in the periodic table, where the elements are show with their chemical symbol.
The chemical symbol of sodium is Na. It is located in the group (colum) 1 and period (raw) 3. There you find that the atomic number is 11. Hence your drawing must show 11 protons.
Since the atom is neutral, the number of electrons is also 11. So, you must place the electrons in the following energy levels or shells:
Main energy level shell number of electrons
n = 1 K 2 (this is the maximum in this level)
n= 2 L 8 (this is the maximun in this level)
n= 3 M 1 (the maximum in this level is 18)
Now that you have the number of protons and the location of the electrons, you must determine the number of neutrons.
In the periodict table you will also find the atomic mass of the elements. The atomic mass of sodium is 22.990 amu. That means that most sodium atoms have mass number (number of protons plus neutrons) 23. Some isotopes will have less neutrons, but you can draw your model using the most typical isotope with 23 nucleons. This means, that the number of neutrons is 23 nucleons - 11 protons = 12 neutrons.
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Answer:
a) 4NH₃ + 6NO ⇄ 6H₂O + 5N₂
b) 2H₂S + 3O₂ ⇄ 2H₂O + 2SO₂
Explanation:
Write the equation as given then modify accordingly.
a) NH3 + NO ⇄ H2O + N2
make sure that the amount of each element is equal in both side (reactants and products)
Hydrogen is the different one thus to make H egal we multiply by 2 in the reactant and by 3 in the product to make it 6. Thus the all reaction is multiply accordingly.
2NH3 + 3NO ⇄ 3H2O + 5/2N2
to remove the fraction, multiply both side by 2.
4NH3 + 6NO ⇄ 6H2O + 5N2
b) O2 + H2S ⇄ H2O + SO2
The Oxygen are not the same, so we make them equal to 6 in both side. in the reactant we have to multiply by 3. In the product we have to get 2 for water and 2 for SO2 to have a total of 6 O.
we modify the reaction accordingly to equal elements in both side.
2H2S + 3O2 ⇄ 2H2O + 2SO2