<h3>
Answer: Si (choice D)</h3>
This is the element Silicon.
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Explanation:
First convert each percentage to its decimal form.
For example, 92.2297% converts to 0.922297 after moving the decimal point two spots to the left.
After doing that, multiply those decimal values with their respective atomic mass unit (amu) values.
- 27.9769 * 0.922297 = 25.8030109393
- 28.9765 * 0.046832 = 1.357027448
- 29.9738 * 0.030872 = 0.9253511536
Then we add up the results
25.8030109393 + 1.357027448 + 0.9253511536 = 28.0853895409
That rounds to about 28.085
Then look at the periodic table to see the atomic mass of Cobalt (Co), Aluminum (Al), Nickel (Ni) and Silicon (Si). The mass values listed in the periodic table are weighted averages of all the isotopes. The units for the mass are still in amu.
- Cobalt = 58.933
- Aluminum = 26.982
- Nickel = 58.693
- Silicon = 28.085
We have a match with silicon, showing that <u>choice D</u> is the final answer.
Answer:
yh
Explanation:
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The gases that get released form bubbles in the solution
NO₂ is a brown gas while N₂O₄ is colorless. If heating causes a brown color to persist, then this means that heating causes the reaction to shift backwards and produce NO₂. Therefore, the reaction must be exothermic.
Answer:
See detailed mechanism in the image attached
Explanation:
The mechanism shown in detail below is the synthesis of serine in steps.
The first step is the attack of the ethoxide ion base on the diethyl acetamidomalonate substrate giving the enolate and formaldehyde.
The second step is the protonation of the oxyanion from (1) above to form an alcohol as shown.
Acid hydrolysis of the alcohol formed in (3) above yields a tetrahedral intermediate, a dicarboxyamino alcohol.
Decarboxylation of this dicarboxyamino alcohol yields serine, the final product as shown in the image attached.