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kvv77 [185]
2 years ago
11

How many half-lives must elapse until 84 % of a radioactive sample of atoms has decayed? -g?

Chemistry
1 answer:
Ivahew [28]2 years ago
4 0
Half-life is the time required for decay of 50% of radio-active nuclei.

Thus, when radio-active material crosses 1st half-life, 100/2 = 50% radio-active material is left and remaining 50% is elapsed.

When, when radio-active material crosses 2nd half-life, 50/2 = 25% radio-active material is left and remaining 75% is elapsed.

When radio-active material crosses 3rd half-life, 25/2 = 12.5% radio-active material is left and remaining 87.5% is elapsed.

Thus, 2 <span>half-lives must elapse until 84 % of a radioactive sample of atoms has decayed.</span>
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Name two hormones produced by the endocrine system and describe how they work with other organ systems to maintain homeostasis
Annette [7]
The 2 hormones are insulin & glucagon.

A hormone will only act on a part of the body it 'fits'. A hormone can be thought of as a key, and its target site ( i.e an organ) has specially shaped locks on the cell walls. 
If the hormone fits, then it will work.

The hormone can set off a cascade of other singling pathways in the cell to cause an immediate effect ( for instance, insulin signaling leads to a rapid uptake of glucose in muscle cells)

The endocrine system is a tightly regulated system that keeps the hormones and their effects at just the right level. One way this is achieved is through ' feedback loops'. The release of hormones is regulated by other hormones, proteins or neuronal signals.

The released hormone then has its effect on other organs. This effect on the organ feeds back to the original signal to control any further hormone release.


btw- found all this info @ the Better Health channel, an australian government health website , so if your still confused by my answer, check out this website

www.betterhealth.vic.gov.au/health/conditionsandtreatments/hormonal-endocrine-system

8 0
3 years ago
Read 2 more answers
True or false, when a material loses thermal energy, it usually contracts.
Brums [2.3K]

Answer:

True

Explanation:

Whenever something loses thermal energy, it contracts and becomes smaller.

8 0
2 years ago
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How many moles of sodium cyanide are needed to react completely with 2.6 moles of sulfuric acid
Tanya [424]

7.2 mol NacN



Is the answer



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4 0
3 years ago
In which color coded area would you find an element that behaves both like a metal and a non-metal?
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what elements are each color over? can you list one from each color so i can answer it

4 0
2 years ago
What is the molarity of 5.63 moles of lithium in 3.25 liters of solution
luda_lava [24]

Answer:

1.73 Molar

Explanation:

The formula is Molarity=moles of solute/liters of solution, which can be written in whatever way you prefer, and examples include: M=N/V or M=mol/L.

M=N/V

M= \frac{5.63}{3.25}

Divide 5.63 by 3.25. When you calculate this, you get 1.73, therefore your answer is 1.73 molar.

5 0
3 years ago
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