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jok3333 [9.3K]
2 years ago
7

What percentage of a substance remains after 7 half-lives have passed?

Chemistry
1 answer:
Mila [183]2 years ago
5 0

Answer:

Not really sure, buts its either B or C.

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Describe how oxidation and reduction involve electrons, change oxidation numbers, and combine in
Sholpan [36]

Answer:

Redox

Explanation:

Reduction is gain of electrons

oxidation is loss of electrons

3 0
3 years ago
A student is doing an experiment to determine the effects of temperature on an object. He writes down that the initial temperatu
bogdanovich [222]

Answer:

1) The Kelvin temperature cannot be negative

2) The Kelvin degree is written as K, not ºK

Explanation:

The temperature of an object can be written using different temperature scales.

The two most important scales are:

- Celsius scale: the Celsius degree is indicated with ºC. It is based on the freezing point of water (placed at 0ºC) and the boiling point of water (100ºC).

- Kelvin scale: the Kelvin is indicated with K. it is based on the concept of "absolute zero" temperature, which is the temperature at which matter stops moving, and it is placed at zero Kelvin (0 K), so this scale cannot have negative temperatures, since 0 K is the lowest possible temperature.

The expression to convert from Celsius degrees to Kelvin is:

T(K)=T(^{\circ}C)+273.15

Therefore  in this problem, since the student reported a temperature of -3.5 ºK, the errors done are:

1) The Kelvin temperature cannot be negative

2) The Kelvin degree is written as K, not ºK

6 0
3 years ago
Would the ph at the equivalence point be acidic, basic, or neutral for each given titration?.
Lesechka [4]

Answer:

At the equivalence point, equal amounts of H+ and OH– ions will combine to form H2O, resulting in a pH of 7.0 (neutral). The pH at the equivalence point for this titration will always be 7.0, note that this is true only for titrations of strong acid with strong base.

Explanation:

3 0
2 years ago
How many federal agencies are responsible for managing land resources in the United States?
dimulka [17.4K]

The answer would be 4.

The agencies are:

Department of Agriculture's Forest Service (AFS)

Department of the Interior's Bureau of Land Management (BLM)

Fish and Wildlife Service (FWS)

National Park Service (NPS)

These four agencies cover around 95% of the land and are the only federal agencies.

I learned about these agencies in school.

5 0
2 years ago
What are the sign and magnitude of the charge of atom containing 14 protons, 15 neutrons, and 12 electrons?
Karo-lina-s [1.5K]
<span>We know that protons gives positive charge, neutrons no charge and electrons negative, then +14 - 12 = +2 So the charge of the atom is sign positive and magnitude 2</span>
7 0
3 years ago
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