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4 years ago

How does an elements period number related to the number of the energy level of its valence electrons?

1 answer:

3 0

<span>There is a direct correlation between the period number and the energy level for valence electrons. For example, the H and He elements, in period 1, have their outer electrons in the energy level "1". This continues down the rows: all the elements in period 2 have their principal energy level as n = 2, period 3 has n = 3, and so on.</span>

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Determine how many moles of O2 are required to react completely with 6.7 moles C6H14.

Mice21 [21]

I think *extra stress on the word think lol* it's 6.7 moles of O₂.
unless you have the full formula, giving me the amount of moles in C₆H₁₄ and O₂.

hopefully this helps. :/

8 0

4 years ago

Symbols used in equations, together with the explanations of the symbols, are shown below. which set is correct?

vaieri [72.5K]

Number 4 : solid product

3 0

3 years ago

Read 2 more answers

Estimate the surface-to-volume ratio of a C60 fullerene by treating the molecule as a hollow sphere and using 77pm for the atomi

AleksAgata [21]

Answer:

The surface-to-volume ratio of a C-60 fullerene is 3:77.

Explanation:

Surface area of sphere = $S=4\pi r^2$

Volume of the sphere = $V=\frac{4}{3}\pi r^3$

where : r = radius of the sphere

Radius of the C-60 fullerene sphere = r = 77 pm

Surface area of the C-60 fullerene = $S=4\pi (77 pm)^2$ ...[1]

Volume area of the C-60 fullerene = $V=\frac{4}{3}\pi (77 pm)^3$ ..[2]

Dividing [1] by [2]:

$\frac{S}{V}=\frac{4\pi (77 pm)^2}{\frac{4}{3}\pi (77 pm)^3}$

$=\frac{3}{77}$

The surface-to-volume ratio of a C-60 fullerene is 3:77.

7 0

3 years ago

If antique brass is 30.0% zinc and 70.0% copper, how many grams of antique brass can be made from 18.0 grams of zinc and 32.8 gr

wariber [46]

Answer: 51.86

Explanation:

3 0

3 years ago

You are asked to identify compound X (a white, crystalline solid), which was extracted from a plant seized by customs inspectors

igor_vitrenko [27]

Answer:

C2H2O4

Explanation:

To get the molecular formula, we first get the empirical formula. This can be done by dividing the percentage compositions by the atomic masses. The percentage compositions are shown as follows :

C = 26.86%

H = 2.239%

O = 100 - ( 26.86 + 2.239) = 70.901%

We then proceed to divide by their atomic masses. Atomic mass of carbon is 12 a.m.u , H = 1 a.m.u , O = 16 a.m.u

The division is as follows:

C = 26.86/12 = 2.2383

H = 2.239/1 = 2.239

O = 70.901/16 = 4.4313

We now divide each by the smallest number I.e 2.2383

C = 2.2383/2.2383 = 1

H = 2.239/2.2383 = 1

O = 4.4313/2.2383 = 1.98 = 2

Thus, the empirical formula is CHO2.

To get the molecular formula, we use the molar mass .

(CHO2)n = 90

We add the atomic masses multiplied by n.

(12 + 1 + 2(16))n = 90

45n = 90

n = 90/45 = 2.

Thus , the molecular formula is C2H2O4

4 0

3 years ago