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3 years ago

What minimum frequency of light is required to ionize potassium?The energy required to ionize potassium is 419kJ/mol?

1 answer:

7 0

We find the work function per atom e = E/N = 419000/6.023E23 = hf = photon energy; solve for the frequency, using N = 6.023E23 atoms per mole and Planck's h = 6.63E-34 J.s:

f = E/Nh = 419000/(6.023E23*6.63E-34) = 1.04927E+15 = 1.05E15 cps IS THE ANSWER, HOPE IT HELPED :)

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Which of the following is NOT an effect of human development on the Everglades?

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Answer: I think its A

Explanation:

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PLEASE HELP it would be really nice of you to answer this question i would be very grateful <3

Aleksandr-060686 [28]

Answer: D (The abundance percentage of each isotope)

Explanation: hope this helps!

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How many moles of Calcium Oxide are needed to produce 4 moles of Calcium Hydroxide?

Tpy6a [65]

Taking into account the reaction stoichiometry, 2 moles of CaO are required to react with 2 moles of Ca(OH)₂.

<h3>Reaction stoichiometry</h3>

In first place, the balanced reaction is:

CaO + H₂O → Ca(OH)₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

CaO: 1 mole
H₂O: 1 mole
Ca(OH)₂: 1 mole

<h3>Moles of CaO required</h3>

The following rule of three can be applied: If by stoichiometric reaction 1 mole of Ca(OH)₂ is produced by 1 mole of CaO, 2 moles of Ca(OH)₂ are produced by how many moles of CaO?

$moles of CaO=\frac{2 moles of Ca(OH)_{2}x1 mol of CaO }{1 mole of Ca(OH)_{2}}$

moles of CaO= 2 moles

Finally, 2 moles of CaO are required to react with 2 moles of Ca(OH)₂.

Learn more about the reaction stoichiometry:

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5 0

2 years ago

In a reaction vessel, 17.6 g of solid chromium(III) oxide, Cr2O3, was allowed to react with excess carbon tetrachloride in the f

notsponge [240]

Answer:

72.53% is the yield of CrCl3

Explanation:

Given

Reaction:

Cr2O3(s) + 3 CCl4(l) → 2 CrCl3(s) + 3 COCl2(aq)

CCl4 is in excess and 17.6g Cr2O3 present

The reaction yields 26.6g of CrCl3

To Find:

% yields of the reaction

Also given

Molar mass of CrCl3 = 158.35g/mol

Molar mass of Cr2O3 = 152.00 g/mol

By the stoichiometry of the reaction

1 mole of Cr2O3 gives 2 moles of CrCl3

1 x1 52 g of Cr2O3 gives 2x 158.35 g of CrCl3

= 1 52 g of Cr2O3 gives 316.70 g of CrCl3

17.6 g of Cr2O3 gives (17.6÷152) × 316.70 g CrCl3

= 36.67 g CrCl3

but actual yield is only 26.6g

so % yield is (26.6 ÷÷ 36.67) × 100

= 72.53% is the yield of CrCl3

8 0

3 years ago

What is produced when 50mLs of carbon and 30mLs of oxygen react

dsp73

50ml of carbon dioxide.

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3 0

3 years ago