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Mariulka [41]
3 years ago
10

URGENT PLZ HELP AHHHHHHH

Chemistry
1 answer:
dexar [7]3 years ago
8 0

A, B, and D. You already answered the first one, so I wouldn't think this would be too hard

:)

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What two elements were named after the United States?
kenny6666 [7]
Californium which is element 98, and americium:) those are a couple!! Hope that helps
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3 years ago
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The value of Zeff for a valence electron in an atom of silicon is?
lutik1710 [3]

Zeff is the effective nuclear charge wherein, Z resembles the number of protons in the nucleus while S corresponds to the number of non-valence electrons.

Zeff = Z - S

Silicon has 14 protons; its electron configuration is [Ne] 3s2 3p2. Its non-valence electrons is in the n = 1 and n =2 shells. There are 2 electrons in n = 1 and 8 in n = 2, so there are a total of 10 non-valence electron.

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6 0
3 years ago
Explain why energy sources do not have 100% efficiency. Why do you think some have lower efficiencies?
bearhunter [10]

Answer:

Energy sources do not have 100% efficiency because <em>the processes of energy conversion to usable forms involves energy losses. </em>

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Explanation:

The desired form of energy for use is derived from conversion of energy from the source using an energy converter into another form which is usable. The efficiency of the energy converter is calculated as;

л = output energy/input energy

The efficiency of energy is limited to the cost of equipment required for conversion from energy source by the energy converter to a form which is usable. Additionally, because energy sources are scarce, the technology to use in energy  conversion is a factor affecting energy efficiency in that high efficiency will require advanced technology with better equipment leading higher costs of that energy form. when heat losses are involved during energy conversion, efficiency lowers, thus its better if such losses are used as energy input in another system.

5 0
3 years ago
A velocity-time graph shows how what changes over time?
finlep [7]

Answer:

A velocity-time graph shows how velocity changes over time. The sprinter's velocity increases for the first 4 seconds of the race, it remains constant for the next 3 seconds, and it decreases during the last 3 seconds after she crosses the finish line.

4 0
3 years ago
I need help with #10 (a,b and c) please and thank you!
Sidana [21]

a. An oxidation reaction. An oxidation reaction is a type of chemical reaction that involves a transfer of electrons between two species.

6 0
3 years ago
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