a 5.00 L sample of helium expands to 12.0 L at which point the pressure is measured to be 0.720atm. what was the original pressu

The atomic number of the element indicated by the model is 8, corresponding to option 'C' in the question.

To calculate the moles of MgSO4.7H2O, we find the molar mass equals 246, thus moles = 32 / 246 = 0.13 moles. Upon heating, all 7 H2O from one molecule will evaporate. The total moles of H2O present amount to 7 x 0.13 = 0.91, and the mass of that H2O is 0.91 x 18 = 16.38g. Therefore, the mass of the anhydrous MgSO4 that remains is 32 - 16.38 = 15.62 g.

Result: The count of bonding electrons and non-bonding electrons amounts to (4, 18).

Explanation:

The Lewis-dot structure reveals the number of bonding and non-bonding electrons in .

Lewis-dot representation: It illustrates the valence electron count for atoms in a molecule and shows how they bond, as well as any lone pairs of electrons.

In this structure, 'Xe' is the central atom while 'F' is the terminal atom.

Xenon comprises 8 valence electrons, whereas fluorine contains 7.

The total number of valence electrons in is calculated as 8 + 2(7) = 22 electrons

From the Lewis-dot structure, we can determine

The count of electrons involved in bonding = 4

The count of electrons involved in non-bonding (lone-pairs) = 22 - 4 = 18

Thus, the bonding and non-bonding electron counts are (4, 18).

Below is the Lewis-dot structure for .

Vegetation cover serves as the most efficient and effective method to curb sediment loss. The roots of plants like grass interlink soil particles, aiding in erosion resistance, particularly against runoff water. Vegetation absorbs the force of raindrops, preventing soil particle detachment. Additionally, plants can lie flat resembling shingles on a roof, enabling runoff to travel over the soil rather than disturbing it. Tall, erect vegetation functions as a barrier against wind, diminishing its force so that it cannot dislodge soil particles from the ground surface.

Co2 is indeed the correct answer, my friend.