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Morgarella [4.7K]
3 years ago
7

Whats the si unit chemist use to measure the amount of an element substance?

Chemistry
1 answer:
Westkost [7]3 years ago
4 0
The SI unit for the amount of substance present is the mole.

The mole is defined as the amount of substance that has the same amount of particles as there are atoms in 12 grams of carbon-12. Mathematically, the moles of a substance may be computed using:

moles present = mass of substance / molecular mass of substance
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Determine if these molecules and ion are polar.
Colt1911 [192]

Answer:

a. Polar

b. Polar

c. Non-polar

d. Non-polar

Explanation:

a. H_3O^+, hydronium cation contains a positive charge. Just as any other ion, it is polar, as it has a net charge.

b. H_2S has the same shape as water. There are two lone pairs on sulfur atom which produce an overall dipole moment in this molecule, the bent structure is polar.

c. PCl_5 is non-polar, as the central atom, phosphorus, doesn't contain any lone pairs, all the dipole moments cancel out: two dipole moments in the vertical plane, P-Cl, and three P-Cl dipoles in the horizontal plane within a trigonal bipyramidal shape.

d. CF_4 is non-polar, since it's a tetrahedral molecule with no lone pairs on carbon atom, all four C-F dipole moments cancel out to yield a net 0 dipole moment.

3 0
3 years ago
Can you guys help me with this one part?
Pani-rosa [81]

Answer: Do want the experiment done or help of the experiment

3 0
3 years ago
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If the energy of photon emitted from the hydrogen atom is 4.09 x 10-19 J, what is
Aliun [14]

Answer:

486 nm

Explanation:

From the question given above, the following data were obtained:

Energy (E) = 4.09×10¯¹⁹ J

Wavelength (λ) =?

Next, we shall determine the frequency of the photon. This can be obtained as follow:

Energy (E) = 4.09×10¯¹⁹ J

Planck's constant (h) = 6.63×10¯³⁴ Js

Frequency (f) =?

E = hf

4.09×10¯¹⁹ = 6.63×10¯³⁴ × f

Divide both side by 6.63×10¯³⁴

f = 4.09×10¯¹⁹ / 6.63×10¯³⁴

f = 6.17×10¹⁴ Hz

Next, we shall determine the wavelength of the photon. This can be obtained as follow:

Frequency (f) = 6.17×10¹⁴ Hz

Velocity of photon (v) = 3×10⁸ m/s

Wavelength (λ) =?

v = λf

3×10⁸ = λ × 6.17×10¹⁴

Divide both side by 6.17×10¹⁴

λ = 3×10⁸ / 6.17×10¹⁴

λ = 4.86×10¯⁷ m

Finally, we shall convert 4.86×10¯⁷ m to nm. This can be obtained as follow:

1 m = 1×10⁹ nm

Therefore,

4.86×10¯⁷ m = 4.86×10¯⁷ m × 1×10⁹ nm / 1 m

4.86×10¯⁷ m = 486 nm

Therefore, the wavelength of the photon is 486 nm

7 0
3 years ago
how does getting funding from the government affect scientific research?? a- the government helps the scientist decide what rese
sertanlavr [38]

Answer:

d- Scientists have to follow government rules made to protect people.

Explanation:

Scientific research fosters our understanding of the world around us. It helps people to learn to promote critical thought and problem-solving.  Although there may not be an immediate practical use of the research, in the long term the study could benefit humanity. Scientific research is the product of creative ideas and collaborative communication that the proper role of government is often restricted to funding the research. The role of the government is to perform its reasonable and valid duties of defending human rights and enhancing the independence of the human.

4 0
3 years ago
Who was the first person to discover the existence of electrons​
k0ka [10]
Electron was discovered by J. J. Thomson in 1897 when he was studying the properties of cathode ray.
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3 years ago
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