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natima [27]
3 years ago
10

The human eye is a complex sensing device for visible light. The optic nerve needs a minimum of 2.0 × 10−17 J of energy to trigg

er a series of impulses that eventually reach the brain. How many photons of blue light (475 nm) are needed?
Chemistry
1 answer:
AveGali [126]3 years ago
7 0
Number of photons can be calculated by dividing the needed energy by the energy per photon.

The minimum energy needed is given as 2 x 10^-17 joules
Energy per photon = hc / lambda where h is planck's constant, c is the speed of light and lambda is the wavelength
Energy per photon = (<span>6.626 x 10^-34 x 3 x 10^8) / (475 x 10^-9)
                              = 4.18 x 10^-19 J

number of photons = (2 x 10^-17) / (4.18 x 10^-19)
                               = 47.79 photons which is approximately 48 photons</span>
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What characteristics are used to clarify an area as a wetland?
Nadya [2.5K]
Soil covered, saturated, submerged, flooded w water, standing water
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3 years ago
Suppose you will fill a glass with ice cubes. When the ice cubes melt, is the glass still full
goblinko [34]
No. It will not still be full. The reason being is because when it melts, it's almost the same thing as compacting things down into another object (container). Therefore, you will have some room left i the glass. Like, if your trashcan was over-flowing, and you push it down to compact it so you can add more trash. So when the ice melts, it will not be full.
7 0
3 years ago
You collect 552 mL of argon gas at 23.0 C. What volume will the gas occupy at 46.0C if the pressure remains constant?
taurus [48]

Answer:

1027.9 mL

Explanation:

Formula P1 x V1 / T1 = P2 x V2 / T2

Fill in what you know

Pressure is constant so no need to put that in making the formula

V1 / T1 = V2 / T2

Voulme 1= 950 mL

Volume 2= ?

Temperature 1 = 25 C

Temperature 2 = 50 C

Explanation:

Formula P1 x V1 / T1 = P2 x V2 / T2

Fill in what you know

Pressure is constant so no need to put that in making the formula

V1 / T1 = V2 / T2

Voulme 1= 950 mL

Volume 2= ?

Temperature 1 = 25 C

Temperature 2 = 50 C

8 0
2 years ago
A 53. 5 mL ample of an 5. 4 % (m / v) KBr olution i diluted with water o that the final volume i 205. 0 mL Expre your anwer to t
gogolik [260]

The concentration after dilution is 1.4%.

We are aware that concentration and volume are related to each other by the formula -

C_{1} V_{1} = C_{2} V_{2}, where we have initial concentration and volume on Left Hand Side and final concentration and volume on Right Hand Side.

Keep the values to calculate final concentration.

C_{2} = (53.5 × 5.4)/205.0

Performing multiplication on Right and Side

C_{2} = 288.9/205.0

Performing division on Right Hand Side

C_{2} = 1.4%

Hence, the final concentration is 1.4%.

Learn more about concentration -

brainly.com/question/17206790

#SPJ4

The complete question is -

A 53.5 mL sample of an 5.4 % (m/v) KBr solution is diluted with water so that the final volume is 205.0 mL.

Calculate the final concentration and express your answer to two significant figures and include the appropriate units.

3 0
1 year ago
9. If 28.56 g of K2O is produced when 25.00 g K is reactedaccording to the following equation, what is the percent yieldof the r
Mumz [18]

Answer

b. 95%

Explanation

Given:

Mass of K₂O produced (actual yield) = 28.56 g

Mass of K that reacted = 25.00 g

Equation: 4K(s) + O₂(g) → 2K₂0(s)

What to find:

The percent yield of K₂O.

Step-by-step solution:

The first step is to calculate the theoretical yield of K₂O produced.

From the balanced equation, 4 mol K produced 2 mol K₂O

Molar mass of K₂O = 94.20 g/mol)

Molar mass of K = 39.10 g/mol)

This means 4 mol x 39.10 g/mol = 156.40 g K produced 2 mol x 94.20 g/mol = 188.40 g K₂O

So 25.00 g K will produce:

\frac{25.00\text{ }g\text{ }K\times188.40\text{ }g\text{ }K₂O}{156.40\text{ }g\text{ }K}=30.1151\text{ }g\text{ }K₂O

Actual yield of K₂O = 28.56 g

Theoretical yield of k₂O = 30.1151 g

The percent yield for the reaction can now be calculated using the formula below:

\begin{gathered} Percent\text{ }yield=\frac{Actual\text{ }yield}{Theoretical\text{ }yield}\times100\% \\  \\ Percent\text{ }yield=\frac{28.56\text{ }g}{30.1151\text{ }g}\times100\% \\  \\ Percent\text{ }yield=0.9484\times100\% \\  \\ Percent\text{ }yield=94.84\%\approx95\% \end{gathered}

Therefore, the percent yield for the reaction is 95%.

3 0
1 year ago
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