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fredd [130]
3 years ago
8

Type the correct answer in each box. In an atom, the first energy level can hold electrons. The second energy level can hold ele

ctrons. The third energy level can hold electrons.
Chemistry
1 answer:
Elis [28]3 years ago
4 0
I might be wrong but I think its 2 then 4 then 8
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The illumination of an object by a light source is directly proportional to the strength of the source and inversely proportiona
ElenaW [278]
<span>Exactly 4(4 - 2*2^(1/3) + 2^(2/3)) feet, or approximately 12.27023581 feet. Let's first create an equation to calculate the relative intensity of the light based upon the distance D from the brighter light source. The distance from the dimmer light source will of course be (20-D). So the equation will be: B = 4/D^2 + 1/(20-D)^2 The minimum and maximum can only occur at those points where the slope of the equation is 0. And you can determine the slope by using the first derivative. So let's calculate the first derivative. B = 4/D^2 + 1/(20-D)^2 B' = d/dD [ 4/D^2 + 1/(20-D)^2 ] B' = 4 * d/dD [ 1/D^2 ] + d/dD [ 1/(20-D)^2 ] B' = 4(-2)D^(-3) + (-2)(20 - D)^(-3) * d/dD [ 20-D ] B' = -8/D^3 - 2( d/dD [ 20 ] - d/dD [ D ] )/(20 - D)^3 B' = -8/D^3 - 2(0 - 1)/(20 - D)^3 B' = 2/(20 - D)^3 - 8/D^3 Now let's find a zero. B' = 2/(20 - D)^3 - 8/D^3 0 = 2/(20 - D)^3 - 8/D^3 0 = 2D^3/(D^3(20 - D)^3) - 8(20 - D)^3/(D^3(20 - D)^3) 0 = (2D^3 - 8(20 - D)^3)/(D^3(20 - D)^3) 0 = 2D^3 - 8(20 - D)^3 8(20 - D)^3 = 2D^3 4(20 - D)^3 = D^3 4(8000 - 1200D + 60D^2 - D^3) = D^3 32000 - 4800D + 240D^2 - 4D^3 = D^3 32000 - 4800D + 240D^2 - 5D^3 = 0 6400 - 960D + 48D^2 - D^3 = 0 -6400 + 960D - 48D^2 + D^3 = 0 D^3 - 48D^2 + 960D - 6400 = 0 We now have a simple cubic equation that we can use the cubic formulas to solve. Q = (3*960 - (-48)^2)/9 = 64 R = (9*(-48)*960 - 27*(-6400) - 2*(-48)^3)/54 = -384 D = Q^3 + R^2 = 64^3 + (-384)^2 = 409600 Since the value D is positive, there are 2 imaginary and 1 real root. We're only interested in the real root. S = cbrt(-384 + sqrt(409600)) S = cbrt(-384 + 640) S = cbrt(256) S = 4cbrt(4) T = cbrt(-384 - sqrt(409600)) T = cbrt(-384 - 640) T = cbrt(-1024) T = -8cbrt(2) The root will be 4cbrt(4) - 8cbrt(2) + 48/3 So simplify 4cbrt(4) - 8cbrt(2) + 48/3 =4cbrt(4) - 8cbrt(2) + 16 =4(cbrt(4) - 2cbrt(2) + 4) = 4(4 - 2*2^(1/3) + 2^(2/3)) Which is approximately 12.27023581 This result surprises me. I would expect the minimum to happen where the intensity of both light sources match which would be at a distance of 2/3 * 20 = 13.3333 from the brighter light source. Let's verify the calculated value. Using the brightness equation at the top we have: B = 4/D^2 + 1/(20-D)^2 Using the calculated value of 12.27023581, we get B = 4/D^2 + 1/(20-D)^2 B = 4/12.27023581^2 + 1/(20-12.27023581)^2 B = 4/12.27023581^2 + 1/7.72976419^2 B = 4/150.5586868 + 1/59.74925443 B = 0.026567713 + 0.016736611 B = 0.043304324 And the intuition value of 13.33333333 B = 4/D^2 + 1/(20-D)^2 B = 4/13.33333333^2 + 1/(20-13.33333333)^2 B = 4/13.33333333^2 + 1/6.666666667^2 B = 4/177.7777778 + 1/44.44444444 B = 0.0225 +0.0225 B = 0.045 And the calculated value is dimmer. So intuition wasn't correct. So the object should be placed 4(4 - 2*2^(1/3) + 2^(2/3)) feet from the stronger light source, or approximately 12.27023581 feet.</span>
5 0
3 years ago
What mass of water must be added to 5g of nacl to make 5% mass persentage of the solution?
Vitek1552 [10]

Answer:-

95 grams

Explanation:-

Let the mass of water to be added be M

So total mass = 5 + M

So 5% of this solution has 5g of NaCl by mass.

∴ (M+5) x (5/100) = 5

M+5 = 5 x 100/5

M+5=100

M= 100-5

95

So amount of water to be added is 95 gram

8 0
3 years ago
.400 moles of CO2 gas are confined in a 5.00-liter container at 25 °C. Calculate the pressure exerted in atmospheres and mm Hg.
solong [7]

The pressure exerted by 0.400 moles of carbon dioxide in a 5.00 Liter container at 25 °C would be 1.9563 atm or  1486.788 mm Hg.

<h3>The ideal gas law</h3>

According to the ideal gas law, the product of the pressure and volume of a gas is a constant.

This can be mathematically expressed as:

pv = nRT

Where:

p = pressure of the gas

v = volume

n = number of moles

R = Rydberg constant (0.08206 L•atm•mol-1K)

T = temperature.

In this case:

p is what we are looking for.

v = 5.00 L

n = 0.400 moles

T = 25 + 273

 = 298 K

Now, let's make p the subject of the formula of the equation.

p = nRT/v

  = 0.400 x 0.08206 x 298/5

  = 1.9563 atm

Recall that: 1 atm = 760 mm Hg

Thus:

1.9563 atm = 1.9563 x 760 mm Hg

                   = 1486.788 mm Hg

In other words, the pressure exerted by the gas in atm is 1.9563 atm and in mm HG is 1486.788 mm Hg.

More on the ideal gas law can be found here: brainly.com/question/28257995

#SPJ1

8 0
1 year ago
The zinc within a copper-plated penny will dissolve in hydrochloric acid if the copper coating is filed down in several spots (s
Mrac [35]

Answer:

Mass of hydrogen gas evolved is 0.0749 grams.

Explanation:

Total pressure of the gases = p = 758 mmHg

Vapor pressure of water = 23.78 mmHg

Pressure of hydrogen gas ,P =  p - 23.78 mmHg = 758 mmHg - 23.78 mmHg

P = 734.22 mmHg = \frac{734.22}{760} atm=0.966 atm

Temperature  of of hydrogen gas ,T= 25°C =298.15 K

Volume of hydrogen gas = V = 0.949 L

Moles of hydrogen gas =n

PV = nRT (Ideal gas equation )

n=\frac{PV}{RT}=\frac{0.966 atm\times 0.949 L}{0.0821 atm L/mol K\times 298.15 K}

n = 0.03745 mol

Moles of hydrogen gas = 0.03745 mol

Mass of  0.03745 moles of hydrogen gas  = 0.03745 mol × 2 g/mol = 0.0749 g

Mass of hydrogen gas evolved is 0.0749 grams.

3 0
3 years ago
Which colour would you expect ekasilicon to be
LiRa [457]

Answer:

it would ether be gray to black or silver to gray and black

Explanation:

because of my calculation ekasillicon would be that color because of the eyes and because of your color seeing .

7 0
2 years ago
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