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LenKa [72]
2 years ago
11

A photon has a frequency of 7.3 × 10–17 Hz. Planck’s constant is 6.63 × 10–34 J•s. The energy of the photon, to the nearest tent

hs place, is _____ × 10–50 J.
Chemistry
2 answers:
yawa3891 [41]2 years ago
7 0

Given:

E = 7.3 × 10–17 Hz                                                                                      

 h= 6.63 × 10–34 J•s

Now <em>E = hf</em>

where E is the energy of the photon                                                          

h is the Planck's constant                                                                          

f is the frequency of the photon

Substituting the values in the equation we get                                        

E= 7.3 × 10^-17 × 6.63 × 10^-34                                                                  

<u>E= 4.8399 × 10^-50  J. </u>                                                                                                      



Monica [59]2 years ago
6 0

Answer:

4.8

Explanation:

just took the edge exam

You might be interested in
Determine the number of moles and mass requested for each reaction in Exercise 4.42.
suter [353]

Answer:

(a) 0.22 mol Cl₂ and 15.4g Cl₂

(b) 2.89.10⁻³ mol O₂ and 0.092g O₂

(c) 8 mol NaNO₃ and 680g NaNO₃

(d) 1,666 mol CO₂ and 73,333 g CO₂

(e) 18.87 CuCO₃ and 2,330g CuCO₃

Explanation:

In most stoichiometry problems there are a few steps that we always need to follow.

  1. Step 1: Write the balanced equation
  2. Step 2: Establish the theoretical relationship between the kind of information we have and the one we are looking for. Those relationships can be found in the balanced equation.
  3. Step 3: Apply conversion factor/s to the data provided in the task based on the relationships we found in the previous step.

(a)

Step 1:

2 Na + Cl₂ ⇄ 2 NaCl

Step 2:

In the balanced equation there are 2 moles of Na, thus 2 x 23g = 46g of Na. <u>46g of Na react with 1 mol of Cl₂</u>. Since the molar mass of Cl₂ is 71g/mol, then <u>46g of Na react with 71g of Cl₂</u>.

Step 3:

10.0gNa.\frac{1molCl_{2} }{46gNa} =0.22molCl_{2}

10.0gNa.\frac{71gCl_{2}}{46gNa} =15.4gCl_{2}

(b)

Step 1:

HgO ⇄ Hg + 0.5 O₂

Step 2:

<u>216.5g of HgO</u> form <u>0.5 moles of O₂</u>. <u>216.5g of HgO</u> form <u>16g of O₂</u>.

Step 3:

1.252gHgO.\frac{0.5molO_{2}}{216.5gHgO} =2.89.10^{-3} molO_{2}

1.252gHgO.\frac{16gO_{2}}{216.5gHgO} =0.092gO_{2}

(c)

Step 1:

NaNO₃ ⇄ NaNO₂ + 0.5 O₂

Step 2:

<u>16g of O₂</u> come from <u>1 mol of NaNO₃</u>. <u>16g of O₂</u> come from <u>85g of NaNO₃</u>.

Step 3:

128gO_{2}.\frac{1molNaNO_{3}}{16gO_{2}} =8mol NaNO_{3}

128gO_{2}.\frac{85gNaNO_{3}}{16gO_{2}} =680gNaNO_{3}

(d)

Step 1:

C + O₂ ⇄ CO₂

Step 2:

<u>12 g of C</u> form <u>1 mol of CO₂</u>. <u>12 g of C</u> form <u>44g of CO₂</u>.

Step 3:

20.0kgC.\frac{1,000gC}{1kgC} .\frac{1molCO_{2}}{12gC} =1,666molCO_{2

[tex]20.0kgC.\frac{1,000gC}{1kgC} .\frac{44gCO_{2}}{12gC} =73,333gCO_{2[/tex]

(e)

Step 1:

CuCO₃ ⇄ CuO + CO₂

Step 2:

<u>79.5g of CuO</u> come from <u>1 mol of CuCO₃</u>. <u>79.5g of CuO</u> come from <u>123.5g of CuCO₃</u>.

Step 3:

1.500kgCuO.\frac{1,000gCuO}{1kgCuO} .\frac{1mol CuCO_{3}}{79.5gCuO} =18.87molCuCO_{3}\\ 1.500kgCuO.\frac{1,000gCuO}{1kgCuO} .\frac{123.5g CuCO_{3}}{79.5gCuO} =2,330gCuCO_{3}

5 0
2 years ago
The table above summarizes data given to a student to evaluate the type of change that took place when substance X was mixed wit
Tamiku [17]

The question is incomplete, the complete question is;

The table above summarizes data given to a student to evaluate the type of change that took place when substance X was mixed with water. The student claimed that the data did not provide enough evidence to determine whether a chemical or physical change took place and that additional tests were needed. Which of the following identifies the best way to gather evidence to support the type of change that occurred when water and Xwere mixed?

A. Measuring the melting point of the mixture of water and X

B. Adding another substance to the mixture of water and X to see whether a solid forms

C Measuring and comparing the masses of the water,  X, and the mixture of water and X

D Measuring the electrical conductivities of X and the mixture of water and X

Answer:

D Measuring the electrical conductivities of X and the mixture of water and X

Explanation:

Unfortunately, I am unable to reproduce the table here. However, from the table,  the temperature of the of the mixture of the solid X and water was 101.6°C. This is above the boiling point of water and way below the temperature of the solid X.

This goes a long way to suggest that there was some kind of interaction between the water and X which accounted for the observed temperature of the system of X in water.

The only way we can be able to confirm if X actually dissolved in water is to measure the conductivity of the water. dissolved solids increase the conductivity of water.

6 0
2 years ago
What vitamin a compounds bind with opsin to form rhodopsin??
irina [24]
The organic compound retinal binds with opsin and forms rhodopsin. Retinal is part of the molecule that is responsible for its color. This part is called chromophore. On the other hand, opsins are the proteins in photoreceptor cells. Retinal bounds with these opsins and forms rhodopsin: the basis of the human vision. Rhodopsin is also a protein.It is the pigment in the retinas of humans and animals.
7 0
2 years ago
I NEED HELP ASAP, WILL MARK BRAINLEST!
Andre45 [30]

Answer:

1. 90%

2. 217.4 g O₂

3. 95.0%

4. Trial 2 ratios

Explanation:

Original: SiCl₄ + O₂ → SiO₂ + Cl₂

Balanced: SiCl₄ + O₂ → SiO₂ + 2Cl₂

Trial        SiCl₄                   O₂                    SiO₂

 1           120 g                  240 g              38.2 g

 2           75 g                   50 g                25.2 g

<u>Percentage yield for trial 1</u>

We need to get actual yield (38.2 g) and theoretical yield, in grams.

Mass to moles:

 molar mass SiCl₄: 28.09 + 4(35.45) = 169.9 g/mol

 120 g SiCl₄ x 1 mol/169.9 g = .706 mol SiCl₄

Moles to moles:

 For each mole SiCl₄, we have one mol SiO₂ based on the balanced rxn.

 .706 mol SiCl₄ = .706 mol SiO₂

Moles to mass:

 molar mass SiO₂: 28.09 + 2(16.00) = 60.09 g/mol

 .706 mol SiO₂ x 60.09g/mol = 42.44 g SiO₂

Theoretical yield:

 actual/theoretical x 100

 38.2 / 42.44 = .900 = <u>90.0% yield</u>

<u>Leftover reactant for trial 1</u>

We know oxygen is the excess reactant.

Mass to moles:

 molar mass O₂ = 32.00 g/mol

 240 g O₂ x 1 mol/32.00 g = 7.5 mol O₂

We used .706 mol SiO₂, so we also used .706 mol O₂.

 7.5 - .706 = 6.8 moles left over

Moles to mass:

 6.8 mol O₂ x 32.00g/mol =<u> 217.4 g O₂</u>

<u />

<u>Percentage yield for trial 2</u>

Mass to moles:

 molar mass SiCl₄: 169.9 g/mol

 75 g SiCl₄ x 1 mol/169.9 g = .441 mol SiCl₄

Moles to moles:

 For each mole SiCl₄, we have one mol SiO₂ based on the balanced rxn.

 .441 mol SiCl₄ = .441 mol SiO₂

Moles to mass:

 molar mass SiO₂: 60.09 g/mol

 .441 mol SiO₂ x 60.09g/mol = 26.5 g SiO₂

Theoretical yield:

 actual/theoretical x 100

 25.2 / 26.5 = .950 = <u>95.0% yield</u>

Because the percentage yield of trial 2 is higher than that of trial 1, we know that the ratio of reactants in trial 2 is more efficient! We got a result closer to our theoretical yield.

6 0
2 years ago
A solution at 25 ∘C has pOH = 10.53. Which of the following statements is or are true? The solution is acidic. The pH of the sol
Lady bird [3.3K]

Answer:

The true statements are:

The solution is acidic

The pH of the solution is 14.00 - 10.53.

10^{-10.53}=[OH^-]

Explanation:

The pH of the solution is defined as negative logarithm of hydrogen ion concentration present in the solution .

pH=-\log[H^+]

  • The pH value more 7 means that hydrogen ion concentration is less ,alkaline will be the solution.
  • The pH value less 7 means that hydrogen ion concentration is more ,acidic will be the solution.
  • The pH value equal to 7 indicates that the solution is neutral.

The pOH of the solution is defined as negative logarithm of hydroxide ion concentration present in the solution .

pOH=-\log[OH^-]

The pOH of the solution = 10.53

10.53=-\log[OH^-]

10^{-10.53}=[OH^-]

The pH of the solution = ?

pH+pOH=14

pH=14-pOH=14-10.53=3.47

Here, the pH of the solution is less than 7 which means that solution acidic.

8 0
2 years ago
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