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3 years ago

1. Name three obstacles that Mendeleev faced in his life?

Chemistry

1 answer:

Fittoniya [83]3 years ago

3 0

Answer:

was difficult to place isotopes of elements as they have the same chemical properties but different atomic masses. It was not possible to predict how many elements could be discovered between two heavy elements as the rise in atomic mass is not uniform.

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Phytoplankton are microscopic photosynthesizing organisms that typically live in the upper layers of the ocean. What trophic lev

alex41 [277]

Answer:

Primary producers

Explanation:

Phytoplankton belong to the primary producers trophic level. Beings of the other levels gain energy from phytoplankton. Phytoplankton are also capable of transforming inorganic carbon into protoplasm.

4 0

4 years ago

A sample of nitrogen goes from 21L to 14L and it's pressure increases from 100kPa to 150kPa. The final temperature is 300K. What

Alik [6]

Answer:

The initial temperature is 300 K (The temperature doesn't change)

Explanation:

Step 1: Data given

Initial volume = 21L

Final volume = 14L

Initial pressure = 100 kPa = 0.986923 atm

Final pressure = 150 kPa = 1.48038 atm

The final temperature = 300K

Step 2: Calculate the initial temperature

Calculate the initial temperature

(P1*V1)/T1 = (P2*V2)/T2

⇒with P1 = the initial pressure = 0.986923 atm

⇒with V1 = the initial volume = 21 L

⇒ with T1 = the initial temperature = ?

⇒with P2 = the final pressure = 1.48038 atm

⇒with V2 = the final volume = 14 L

⇒with T2 = the final temperature = 300 K

(0.986923 * 21)/T1 = (1.48038*14)/300

T1 = 300 K

The initial temperature is 300 K (The temperature doesn't change)

8 0

4 years ago

How many molecules of CH4 are in 24.1 g of this compound?

jok3333 [9.3K]

1) find molar mass of CH₄

$=12.01+4(1.01)\\\\=16.05\ g/mol$

2) determine moles of CH₄

$=24.1g\ CH_{4}\ x\ \frac{1\ mol\ CH_{4}}{16.05g\ CH_{4}}\\\\=1.501557632\ mol\ CH_{4}$

3) multiply by avogadro's number

$=1.501557632\ mol\ CH_{4}\ x\ \frac{6.022\ x\ 10^{23}\ molecules\ CH_{4}}{1\ mol\ CH_{4}} \\\\=9.04238006\ x\ 10^{23}\\\\=9.04\ x\ 10^{23}\ molecules\ CH_{4}$

7 0

2 years ago

Draw the structural formula of the major product of the reaction of (S)-2,2,3-trimethyloxirane with MeOH, H . Use the wedge/hash

Katarina [22]

Answer:

(S)-3-methoxy-3-methylbutan-2-ol

Explanation:

In this case, we have an epoxide opening in acid medium. The first step then is the protonation of the oxygen. Then the epoxide is broken to generate the most stable carbocation. The nucleophile ( $CH_3OH$ ) will attack the carbocation generating a new bond. Finally, the oxygen is deprotonated to obtain an ether functional group and we will obtain the molecule (S)-3-methoxy-3-methylbutan-2-ol.