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2 years ago

Determine the percent composition of all elements in enstatite, MgSiO3, a mineral found in Earth's crust.

2 answers:

8 0

Magnesium:
Mg molar mass: 24.3050
You have one atom of Mg so, 24.211% (mass percent)

Silicon:
Si molar mass: 28.0855
You have one atom of Si so, 27.977% (mass percent)

Oxygen:
O molar mass: 15.9994
You have three atoms so, 47.812% (mass percent)

rusak2 [61]2 years ago

5 0

Explanation:

Percentage of an element in a compound:

$\frac{\text{Number of atoms of element}\times \text{Atomic mass of element}}{\text{molecular mass of compound}}\times 100$

Mass of magnesium atom = 24 g/mol

Mass of silicon atom = 28 g/mol

Mass of oxygen atom = 16 g/mol

Molar mass of $MgSiO_3$ =24 g/mol+28 g/mol+3 × 16 g/mol=100 g/mol

Composition of all elements in enstatite, $MgSiO_3$

Percentage of magnesium :

$\frac{1\times 24 g/mol}{100 g/mol}\times 100=24\%$

Percentage of silicon:

$\frac{1\times 28 g/mol}{100 g/mol}\times 100=28\%$

Percentage of oxygen:

$\frac{3\times 16 g/mol}{100 g/mol}\times 100=48\%$

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In Universe L, recently discovered by an intrepid team of chemists who also happen to have studied interdimensional travel, quan

Advocard [28]

Answer:

Manganese, Fifth transition element

[X] 3d⁶ 4s¹

Iron, Sixth transition element

[X] 3d⁶ 4s²

Explanation:

Complete Question

In Universe L, recently discovered by an intrepid team of chemists who also happen to have studied interdimensional travel, quantum mechanics works as it does in our universe, except that there are six d orbitals instead of the usual number we observe here. Use these facts to write the ground-state electron configurations of the sixth and seventh elements in the first transition series in Universe L. Note; you may use [X] to stand for the electron configuration of the noble gas at the end of the row before the first transition series.

Solution

In our universe, there are 5 d orbitals.

And according to Aufbau's principles that electrons fill the lower energy orbitals before they fill higher energy orbitals and Hund's Rule that states that electrons are fed singly to all the orbitals of a subshell before pairing occurs.

The fifth and sixth transition elements in our universe is then Manganese and Iron respectively.

Manganese - [Ar] 3d⁵ 4s²

Iron - [Ar] 3d⁶ 4s²

So, in the new universe L, where there are six d orbitals, for manganese, the fifth transition metal, because half filled orbitals are more stable than partially filled orbitals (that woukd have been rhe case if we leave 5 electrons on the 3d orbital), the 4s orbital is filled to half of its capacity and the one electron removed from the 4s is used to fill the six 3d orbital to half of its capacity too.

For the sixth transition element, the new extra electron just fills the lower energy 4s orbital, leaving the six 3d orbitals all half-filled.

Hence, they both have ground state configurations of

- Manganese, Fifth transition element

[X] 3d⁶ 4s¹

- Iron, Sixth transition element

[X] 3d⁶ 4s²

Hope this Helps!!!

7 0

2 years ago

What is the mass, in g, of 0.500 mol of 1,2-dibromoethane, CH2BrCH2Br?

inna [77]

Molar mass CH2BrCH2Br = 188.0 g/mol

1 mole ---------- 188.0 g
0.500 moles ----- ?

mass = 0.500 * 188.0 / 1

= 94.0 g

Answer C

hope this helps!

4 0

2 years ago

Titanium has five common isotopes: 46Ti (8.0%), 47Ti (7.8%), 48Ti (73.4%), 49Ti (5.5%), 50 Ti (5.3%). What is the average atomic

zhannawk [14.2K]

(46x8.0)+(47x7.8)+(48x73.4)+(49x5.5)+(50x5.3) = 4792.3

4792.3/100 = 47.923 this is the average atomic mass of Titanium

6 0

2 years ago

If you start with 100 grams of hydrogen-3, how many grams will you have after 24.6 years?

svet-max [94.6K]

Answer:

The mass left after 24.6 years is 25.0563 grams

Explanation:

The given parameters are;

The mass of the hydrogen-3 = 100 grams

The half life of hydrogen-3 which is also known as = 12.32 years

The formula for calculating half-life is given as follows;

$N(t) = N_0 \times \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{\frac{1}{2} }} }$

Where;

N(t) = The mass left after t years

N₀ = The initial mass of the hydrogen-3 = 100 g

t = Time duration of the decay = 24.6 years

$t_{\frac{1}{2} }$ = Half-life = 12.32 years

$N(24.6) = 100 \times \left (\dfrac{1}{2} \right )^{\dfrac{24.6}{12.32}} } = 25.0563$

The mass left after 24.6 years = 25.0563 grams.

4 0

2 years ago

The nitrogen content of organic compounds can be determined by the Dumas method. The compound in question is first reacted by pa

MAVERICK [17]

Answer:

Mass percent of nitrogen in the compound is 13,3%

Explanation:

Dumas method is an analytical method to determine nitrogen content in samples, thus:

CₐHₓNₙ + (2a+x/2) CuO → aCO₂ + ˣ/₂ H₂O + ⁿ/₂ N₂ + (2a+x/2) Cu

As the CO₂ is removed with KOH, in the mixture you have H₂O and N₂

At 25°C. the vapor pressure of water is 23,8 torr, that means that the pressure due to N₂ is:

726torr - 23,8torr = 702,2 torr.

Using gas law:

n = PV/RT

Where:

P is pressure (702,2torr≡ 0,924 atm)

V is volume (0,0318L)

R is gas constant (0,082atmL/molK)

And T is temperature (25°C≡298,15K)

Replacing, number of moles of N₂, n, are:

n = 1,20x10⁻³moles of N₂. In grams:

1,20x10⁻³moles of N₂× $\frac{28g}{1mol}$ = 0,0336 g of N₂.

Thus, mass percent of nitrogen in the compound is:

$\frac{0,0336g N}{0,253gSample}$ ×100= 13,3%

I hope it helps!

7 0

2 years ago