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3 years ago

Which element above has 8 protons in its nucleus?

2 answers:

8 0

Oxygen, you cannot judge an elements number of protons by its atomic mass, but by the atomic number. the atomic number is 8, thus 8 protons.

Nataliya [291]3 years ago

6 0

A. Oxygen. Oxygen has an atomic mass of 16. The atomic mass of an atom is the combined weight o the protons and neutrons. Since Oxygen's atomic mass is 16, it has 8 protons and 8 neutrons.

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Give the number of particles of each element in NH3, ammonia.

Y_Kistochka [10]

You'll need Avogadro's number for this. NH3 has 1 Nitrogen and 2 Hydrogen. You'll multiply the molar mass of each times Avogadro's number. So:

molar mass N x 6.022x10^23 x 1 Nitrogen= total A

Molar mass H x 6.022x10^23 x 2 Hydrogen= total B

Add total A+B = your answer

I don't have a calculator or periodic table but if you plug in the numbers you'll get your answer. Hope it helps.

3 0

3 years ago

17. When you hold a soda can in your hand, you possess trillions and trillions of aluminum atoms. In one paragraph, using

andreev551 [17]

In the early 1900's, Paul Drüde came up with the "sea of electrons" metallic bonding theory by modeling metals as a mixture of atomic cores (atomic cores = positive nuclei + inner shell of electrons) and valence electrons. Metallic bonds occur among metal atoms. Whereas ionic bonds join metals to non-metals, metallic bonding joins a bulk of metal atoms. A sheet of aluminum foil and a copper wire are both places where you can see metallic bonding in action.

Metals tend to have high melting points and boiling points suggesting strong bonds between the atoms. Even a soft metal like sodium (melting point 97.8°C) melts at a considerably higher temperature than the element (neon) which precedes it in the Periodic Table. Sodium has the electronic structure 1s22s22p63s1. When sodium atoms come together, the electron in the 3s atomic orbital of one sodium atom shares space with the corresponding electron on a neighboring atom to form a molecular orbital - in much the same sort of way that a covalent bond is formed.

The difference, however, is that each sodium atom is being touched by eight other sodium atoms - and the sharing occurs between the central atom and the 3s orbitals on all of the eight other atoms. Each of these eight is in turn being touched by eight sodium atoms, which in turn are touched by eight atoms - and so on and so on, until you have taken in all the atoms in that lump of sodium. All of the 3s orbitals on all of the atoms overlap to give a vast number of molecular orbitals that extend over the whole piece of metal. There have to be huge numbers of molecular orbitals, of course, because any orbital can only hold two electrons.

The electrons can move freely within these molecular orbitals, and so each electron becomes detached from its parent atom. The electrons are said to be delocalized. The metal is held together by the strong forces of attraction between the positive nuclei and the delocalized electrons Hope this helped

5 0

3 years ago

luda_lava [24]

Answer:D

Explanation:

4 0

3 years ago

If the vapor pressure of water (<img src="https://tex.z-dn.net/?f=P_%7BH_2O%7D" id="TexFormula1" title="P_{H_2O}" alt="P_{H_2O}"

dmitriy555 [2]

Answer:

739.8 mmHg

Explanation:

By Dalton's Law of Partial Pressures, the total pressure of a gas mixture is the sum of the partial pressure of its components. The partial pressure is the pressure that the substance would have if it was alone in the same conditions of the mixture (same temperature and volume). So:

$P_{total} = P_{H_{2}O} + P_{H_{2}}$

757.3 = 17.5 + $P_{H_{2}}$

$P_{H_{2}}$ = 757.3 - 17.5

$P_{H_{2}}$ = 739.8 mmHg

3 0

3 years ago

Determine the empirical formula for a compound that is 70.79% carbon, 8.91% hydrogen, 4.59% nitrogen, and 15.72% oxygen. determi

IceJOKER [234]

Hello!

We use the amount in grams (mass ratio) based on the composition of the elements, see: (in 100g solution)

C: 70.79% = 70,79 g
H: 8.91% = 8.91 g
N: 4.59% = 4.59 g
O: 15.72% = 15.72 g

Let us use the above mentioned data (in g) and values will be converted to amount of substance (number of moles) by dividing by molecular mass (g / mol) each of the values, lets see:

$C: \dfrac{70.79\:\diagup\!\!\!\!\!g}{12\:\diagup\!\!\!\!\!g/mol} \approx 5.89\:mol$

$H: \dfrac{8.91\:\diagup\!\!\!\!\!g}{1\:\diagup\!\!\!\!\!g/mol} = 8.91\:mol$

$N: \dfrac{4.59\:\diagup\!\!\!\!\!g}{14\:\diagup\!\!\!\!\!g/mol} \approx 0.328\:mol$

$O: \dfrac{15.72\:\diagup\!\!\!\!\!g}{16\:\diagup\!\!\!\!\!g/mol} = 0.9825\:mol$

We note that the values found above are not integers, so let's divide these values by the smallest of them, so that the proportion is not changed, let's see:

$C: \dfrac{5.89}{0.328}\to\:\:\boxed{C\approx 18}$

$H: \dfrac{8.91}{0.328}\to\:\:\boxed{H\approx 27}$

$N: \dfrac{0.328}{0.328}\to\:\:\boxed{N\approx 1}$

$O: \dfrac{0.9825}{0.328}\to\:\:\boxed{O\approx 3}$

T<span>hus, the minimum or empirical formula found for the compound will be:

</span> $\boxed{\boxed{C_{18}H_{27}N_1O_3\:\:or\:\:C_{18}H_{27}NO_3}}\end{array}}\qquad\checkmark$

I hope this helps. =)

5 0

3 years ago