Answer:
- The second choice: <u><em>22 g He </em></u><em>will have the greatest volume at STP</em>
Explanation:
Following Avogadro's principle, under ideal condtions, the <em>volume</em> of the gases at the same conditions of temperature, and pressure, is proportional to the number of molecules.
Then, you can calculate the number of molecules for each of the gases to determine which is the sample with the greatest number of molecules and, hence, which will have the greatest volume at STP (standard temperature and pressure).
The formula to calcualte the number of molecules (in moles) is:
- n = mass in grams / molar mass
Then, since the mass is the same (22 g) for the four options, the result will be dependent on the molar mass: the gass witht the smallest molar mass will give the largest number of moles for 22 g, and will have the greatest volume.
<u><em>a) 22 g CO:</em></u>
- Molar mass of CO ≈ 28 g/mol
<u><em>b) 22 g He:</em></u>
- Molar mass of He ≈ 4.0 g/mol
<em><u>c) 22 g O₂ </u></em>
- Molar mass of O₂ ≈ 32 g/mol
<em><u>d) 22 g Cl₂</u></em>
- Molar mass of Cl₂ ≈ 71 g/mol
<u>Conclusion</u>: since He has the smallest molar mass, the sample of 22 g of He gas will have the greatest volume at STP.
The compound HClO4, when placed in water, will dissociate into the ions, H+ and ClO4-. Therefore, the 2.0 M solution will also form 2.0 M H+. The pH is calculated through the equation,
pH = -log[H+]
Substituting,
pH = -log[2] = -0.3
Thus, the pH of the solution is -0.3.
Answer: B and E: Using fewer wire loops in the solenoid , moving the magnet more slowly
Explanation: I just took the test
I'm quite sure the 'F' is a mistake, and the word is MIXTURE.
Answer:
E - Atomic mass is calculated by weighted atomic average using all the isotope data available.
G - Mass number is equal to the sum of protons and electrons in an atom.
Explanation:
Take an element
- Mass no is 25 and atomic no is 12.