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4 years ago

The mass number of Fez is 56. How many neutrons are there in a single Fez atom?

Chemistry

1 answer:

kumpel [21]4 years ago

6 0

Answer:

Mass number is indicative of the number of protons and neutrons in the nucleus of Fez. The number of protons present in a neutral atom is equal to that of the number of electrons. Hence the number of neutrons present = 56- number of electrons.

Explanation:

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manganese has an atomic number of 25 and an atomic mass of 55 amu. How many particles are found in its nucleus

saw5 [17]

The particles in the nucleus is 55

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3 years ago

A 7.50-g sample of iron is heated in oxygen to form an iron oxide. if 10.71 g of the oxide is formed, what is its empirical form

Zielflug [23.3K]

Answer is: empirical formula is Fe₂O₃.
m(Fe) = 7,50 g.
m(iron oxide) = 10,71 g.
n(Fe) = m(Fe) ÷ M(Fe).
n(Fe) = 7,50 g ÷ 55,85 g/mol = 0,134 mol.
m(O) = m(iron oxide) - m(Fe).
m(O) = 10,71 g - 7,50 g = 3,21 g.
n(O) = 3,21 g ÷ 16 g/mol = 0,20 mol.
n(Fe) : n(O) = 0,134 mol : 0,2 mol = 2 : 3.

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4 years ago

Vanadium (III) hydroxide reacts with hydrobromic acid according to the following balanced chemical equation: V(OH)3 (s) + 3 HBr

9966 [12]

Answer:

TY and I like the country studies.

Explanation:

ok bye por a mathmu n bye for now and hope you have patience.

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3 years ago

Tastes bitter acid or base

zvonat [6]

Base is what tastes bitter.

Associate acids with citrus, like lemons. Acids are sour.
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3 years ago

A) A red laser pointer emits light with a wavelength of 670 nm. What is the frequency of this light?

Serga [27]

Answers:

a) $4.47(10)^{14} Hz$

b) $178254.16 J$

c) $2.96(10)^{-19} J$

Explanation:

a) The following equation states the relation between the wavelength $\lambda$ and the frequency $\nu$ of the light:

$c=\lambda \nu$ (1)

Where:

$c=3(10)^{8}m/s$ is the speed of light in vacuum

$\lambda=670 nm=670(10)^{-9}m$ is the wavelength of the light emitted by the laser pointer

$\nu$ is the frequency

Finding $\nu$ :

$\nu=\frac{c}{\lambda}$ (2)

$\nu=\frac{3(10)^{8}m/s}{670(10)^{-9}m}$ (3)

$\nu=4.47(10)^{14} Hz$ (4) This is the frequency

b) The energy $E$ of a 670 nm photon is given by:

$E=\frac{hc}{\lambda}$ (5)

Where:

$h=6.626(10)^{-34}\frac{m^{2}kg}{s}$ is the Planck constant

Then:

$E=\frac{(6.626(10)^{-34}\frac{m^{2}kg}{s})(3(10)^{8}m/s)}{670(10)^{-9}m}$ (6)

$E=2.96(10)^{-19} J$ (7) This is the energy of one photon

Now we have to find the energy of 1 mole of these 670 nm photons by multiplying (7) by the Avogadro's number ( $N_{A}=6.0221(10)^{23}/mol$ ):

$E N_{A}=(2.96(10)^{-19} \frac{J}{photon})(6.0221(10)^{23}\frac{photon}{mol})$ (8)

$E N_{A}=178254.16 J$ This is the energy of 1 mole of 670 nm photons

c) The ground state of an atom is the point where <u>the energy of the system is zero</u>. This means the ground state energy is $E_{o}=0 J$ and the energy gap $\Delta E$ is:

$\Delta E=E-E_{o}$

$\Delta E=2.96(10)^{-19} J-0 J=2.96(10)^{-19} J$

Hence, the energy gap has the same value that was already calculated in part b (7), which is the energy of 670 nm photons:

$E=2.96(10)^{-19} J$

This is the energy of a single 670 nm photon, which is emitted when the excited electrons return to the ground state.

That is why the wavelength (color) of the light of the laser pointer is 670 nm (red).

8 0

4 years ago