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3 years ago

When 2.50 grams of copper reacts with oxygen?

1 answer:

7 0

Mass oxigen = 2.81 - 2.50 = 0.31 g
Moles O = 0.31 g / 15.9994 g/mol =0.0194

moles Cu = 2.50 g / 63.546 g/mol =0.0393

we divide by the smallest number
0.0194 / 0.0194 = 1 => O
0.0393 / 0.0194 = 2 => Cu
the formula is Cu2O ( Copper (I) oxide )
Ya got this

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Draw a Lewis structure for SO 2 in which all atoms obey the octet rule. Show formal charges. Do not consider ringed structures.

blagie [28]

Answer:

The answer is attached below

Explanation:

To draw the Lewis structure the sulphur willl be placed in the centre with the Valence electron sorrounding it the electrons between sulphu and oxygen to form bonds

5 0

3 years ago

Positional isomers

zimovet [89]

The answer is D) are compounds that have the same number and types of atoms but are arranged differently.

Source: just took the test :)

7 0

3 years ago

Calculate the frequency of the n=2 line in the lyman series of hydrogen

Alona [7]

Answer:

Approximately $2.47\times 10^{15}\; \rm Hz$ .

Explanation:

The Lyman Series of a hydrogen atom are due to electron transitions from energy levels $n \ge 2$ to the ground state where $n = 1$ . In this case, the electron responsible for the line started at $n = 2$ and transitioned to

A hydrogen atom contains only one electron. As a result, Bohr Model provides a good estimate of that electron's energy at different levels.

In Bohr's Model, the equation for an electron at energy level $n$ (

$\displaystyle - \frac{k\, Z^2}{n^2}$ (note the negative sign in front of the fraction,)

where

$k = 2.179 \times 10^{-18}\; \rm J$ is a constant.

$Z$ is the atomic number of that atom. $Z = 1$ for hydrogen.
$n$ is the energy level of that electron.

The electron that produced the $n = 2$ line was initially at the

$\begin{aligned} &E_{n = 2} \cr &= -\frac{k\, Z^2}{n^2} \cr &= -\frac{2.179 \times 10^{-18} \times 1}{2^2} \cr & \approx -5.4475\times 10^{-19}\; \rm J\end{aligned}$ .

The electron would then transit to energy level $n = 1$ . Its energy would become:

$\begin{aligned} &E_{n = 1} \cr &= -\frac{k\, Z^2}{n^2} \cr &= -\frac{2.179 \times 10^{-18} \times 1}{1^2} \cr & \approx -2.179 \times 10^{-18} \; \rm J\end{aligned}$ .

The energy change would be equal to

$\begin{aligned}&\text{Initial Energy} - \text{Final Energy} \cr &= E_{n = 2} - E_{n = 1} \cr &= -5.4475 \times 10^{-19} - \left(-2.179 \times 10^{-18}\right) \cr & \approx 1.63425\times 10^{-18}\; \rm J \end{aligned}$ .

That would be the energy of a photon in that $n = 2$ spectrum line. Planck constant $h$ relates the frequency of a photon to its energy:

$E = h \cdot f$ , where

$E$ is the energy of the photon.
$h \approx 6.62607015\times 10^{-34}\; \rm J \cdot s$ is the Planck constant.
$f$ is the frequency of that photon.

In this case, $E \approx 1.63425 \times 10^{-18}\; \rm J$ . Hence,

$\begin{aligned} f &= \frac{E}{h} \cr &\approx \frac{1.63425\times 10^{-18}}{6.62607015\times 10^{-34}} \cr & \approx 2.47 \times 10^{15}\; \rm s^{-1}\end{aligned}$ .

Note that $1 \; \rm Hz = 1 \; \rm s^{-1}$ .

6 0

3 years ago

Why does hydrochloric acid have a higher boiling point than diatomic fluorine?Why does hydrochloric acid have a higher boiling p

beks73 [17]

Hydrochloric acid is polar which means it has stronger bonds between it's molecules, unlike diatomic fluorine that is non-polar and has weaker bonds. That's why it has a higher boiling point.

8 0

3 years ago

A certain reaction has an activation energy of 66.41 kJ/mol. At what Kelvin temperature will the reaction proceed 3.00 times fas

swat32

Answer : The temperature will be, 392.462 K

Explanation :

According to the Arrhenius equation,

$K=A\times e^{\frac{-Ea}{RT}}$