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2 years ago

How many moles of iron in a sample that contains 7.91×10^23 atoms of iron?

Chemistry

1 answer:

vazorg [7]2 years ago

5 0

Answer: 1.31

Explanation:

No.of moles = given no.of atoms/Avagadro number

= 7.91×10^23 / 6.022 x 10^23

= 1.31

therefore, no.of moles = 1.31

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What is the longest wavelength in the Balmer series? (Hint: the Rydberg constant for Hydrogen is 1.096776×107 1/m, and the Balme

boyakko [2]

<u>Answer:</u> The longest wavelength of light is 656.5 nm

<u>Explanation:</u>

For the longest wavelength, the transition should be from n to n+1, where: n = lower energy level

To calculate the wavelength of light, we use Rydberg's Equation:

$\frac{1}{\lambda}=R_H\left(\frac{1}{n_i^2}-\frac{1}{n_f^2} \right )$

Where,

$\lambda$ = Wavelength of radiation

$R_H$ = Rydberg's Constant = $1.096776\times 10^7m^{-1}$

$n_f$ = Higher energy level = $n_i+1=(2+1)=3$

$n_i$ = Lower energy level = 2 (Balmer series)

Putting the values in above equation, we get:

$\frac{1}{\lambda }=1.096776\times 10^7m^{-1}\left(\frac{1}{2^2}-\frac{1}{3^2} \right )\\\\\lambda =\frac{1}{1.5233\times 10^6m^{-1}}=6.565\times 10^{-7}m$

Converting this into nanometers, we use the conversion factor:

$1m=10^9nm$

So, $6.565\times 10^{-7}m\times (\frac{10^9nm}{1m})=656.5nm$

Hence, the longest wavelength of light is 656.5 nm

4 0

3 years ago

Which statement is true about molecule speed? (1 point)

ANTONII [103]

Faster molecules have fewer collisions than slower molecules is True about molecular speed.

<h3>What is Molecular speed?</h3>

Molecular speed refers to the average distance gases or molecules travelled atca particular time rate.

It is valid in ideal gas, where the molecules do not interact with others.

Average molecular speed = Square root (3 (ideal gas constant) * (Temperature)/m)

Therefore, Faster molecules have fewer collisions than slower molecules is True about molecular speed.

Learn more about molecular speed from the link below.

brainly.com/question/14327643

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2 years ago

Write a net ionic equation for the reaction that occurs when excess hydrochloric acid (aq) and potassium sulfite (aq) are combin

Ket [755]

<u>Answer:</u> The net ionic equation for the given reaction is $2H^+(aq.)+SO_3^{2-}(aq.)\rightarrow H_2O(l)+SO_2(g)$

<u>Explanation:</u>

Net ionic equation of any reaction does not include any spectator ions.

Spectator ions are the ions which do not get involved in a chemical equation. It is also defined as the ions that are found on both the sides of the chemical reaction when it is present in ionic form.

The chemical equation for the reaction of hydrochloric acid and potassium sulfite is given as:

$2HCl(aq.)+K_2SO_3(aq.)\rightarrow 2KCl(aq.)+SO_2(g)+H_2O(l)$

Ionic form of the above equation follows:

$2H^+(aq.)+2Cl^-(aq.)+2K^+(aq.)+SO_3^{2-}(aq.)\rightarrow 2K^+(aq.)+2Cl^-(aq.)+SO_2(g)+H_2O(l)$

As, potassium and chloride ions are present on both the sides of the reaction, thus, it will not be present in the net ionic equation.

The net ionic equation for the above reaction follows:

$2H^+(aq.)+SO_3^{2-}(aq.)\rightarrow SO_2(g)+H_2O(l)$

Hence, the net ionic equation for the given reaction is written above.

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3 years ago

How many atoms are all in one molecule of ferric sulfide

Zina [86]

There is only 1 atom

7 0

3 years ago

Please Please Please help + show the work please! :)

Mazyrski [523]

The gram-formula mass of Sm is 150.36 u, and the gram-formula mass of O is 15.999 u, so the gram-formula mass of SmO is about 150.36+15.999 = 160.36 g/mol.

So, there are about (9.30 * 10^-3)(160.36)=1.49 grams

4 0

2 years ago

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