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natali 33 [55]
2 years ago
5

A metal foil has a threshold frequency of 5.45 \times 10^{14} \text{ } \text{Hz}5.45×10 14 Hz. Which of the colors of visible l

ight have enough energy to eject electrons from this metal? Select all that are correct.Red
Orange
Yellow
Green
Blue
Indigo
Violet

Chemistry
2 answers:
mash [69]2 years ago
8 0

Explanation:

Below is an attachment containing the solution

nalin [4]2 years ago
7 0

Answer:

Green, Blue, Indigo, Violet

Explanation:

According to Einstein's equation of photoelectric effect, the kinetic energy of emitted photoelectron is the difference between the energy of the incident photon and the work function of the metal. The work function of the metal referee to the minimum energy that must be supplied in order to eject an electron from a metal surface. The energy of the incident photon must exceed the work function of the metal.

When we look at the electromagnetic spectrum, only the selected colours have frequency above the threshold frequency as shown by the image attached below.

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How many nickel atoms are contained in a 92.02 mole sample
Vitek1552 [10]

Answer:

By definition, and this is what Avogadro's constant tells you, 1 mole of nickel must contain 6.022⋅1023 atoms of nickel.

Explanation:

6 0
2 years ago
What happens if a cell is unable to get rid of its waste?
Irina18 [472]
A. The cell will not be able to maintain a stable internal environment. 

8 0
3 years ago
Read 2 more answers
The concentration of HCl can be determined by titration with a primary standard such as Na2CO3 (sodium carbonate). The titration
Masteriza [31]

Answer:

The concentration of HCl is 0.275 M

Explanation:

<u>Step 1:</u> Data given

Mass of Na2CO3 = 0.521 grams

Molar mass of Na2CO3 = 105.99 g/mol

Volume of HCl = 35.7 mL

<u>Step 2: </u>The balanced equation:

2HCl + Na2CO3 → 2NaCl + CO2 + H2O

CO3(2-) + 2H+ ---> H2O + CO2

<u>Step 3</u>: Calculate moles of Na2CO3

Moles Na2CO3 = mass Na2CO3 / Molar mass Na2CO3

Moles Na2CO3 = 0.521 grams / 105.99 g/mol

Moles Na2CO3 = 0.0049 moles

<u>Step 4:</u> Calculate moles of HCl

For 1 mol of Na2CO3 consumed, we need 2 moles of HCl

moles of HCL = 2 * 0.0049 = 0.0098 moles HCl

<u>Step 5:</u> Calculate molarity of HCl

Molarity = number of moles of HCl / Volume (liters)

Molarity = 0.0098 moles / 0.0357 L

Molarity = 0.275 M

The concentration of HCl is 0.275 M

4 0
2 years ago
Read 2 more answers
1. A 5.05 g sample of quartz (SiO2) contains 2.36 g of silicon. What are the percentages of silicon
hammer [34]

Answer: B) 46.7% Si and 53.3% O

Explanation:

To calculate the mass percent of element in a given compound, we use the formula:

\text{Mass percent of element}=\frac{\text{Mass of element}}{\text{total mass}}\times 100\%

Mass of quartz  (SiO_2) = 5.05 g

Mass of silicon = 2.36 g

Mass of oxygen = Mass of quartz  (SiO_2) - mass of silicon = 5.05g - 2.36 g = 2.69 g

\text{Mass percent of silicon}=\frac{\text{Mass of silicon}}{\text{total mass of quartz}}\times 100=\frac{2.36}{5.05}\times 100=46.7\%

\text{Mass percent of oxygen}=\frac{\text{Mass of oxygen}}{\text{total mass of quartz}}\times 100=\frac{2.69}{5.05}\times 100=53.3\%

Thus the percentages of silicon and oxygen in quartz are B) 46.7% Si and 53.3% O

6 0
3 years ago
Help Please!!
Ivahew [28]

The first answer would be:

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I believe the second answer would be:

The age of earth. ( I say this because geological time is used to describe timing and the relationship of events in earths history)

I’m not sure about number 3 but I hope this was somewhat useful!!

7 0
2 years ago
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