The half-life of thorium-227 is 18.72 days. How many days are required for three-fourths of a given amount to decay?I'm not quite sure how to set it up to even start working it? help would be appreciated! Thanks!!

Answers

Answer 1

Answer: t½=18.72days
therefore t¾=18.72+½ of 18.72
we have 18.72+9.36=28.08days

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A medium-temperature star like the Sun would most likely emit its most intense radiation as _____. A. Ultraviolet light B. Visible light C. Microwaves D. Radio waves

Answers

Answer:

The correct answer is option B, that is, visible light.

Explanation:

The Sun is a prime source of ultraviolet rays. Although the Sun discharges all of the distinct types of electromagnetic radiation, 99 percent of its rays are in the form of ultraviolet rays, visible light, and infrared rays. The Sun emits radiation all through the electromagnetic spectrum, that is, from extremely high-energy X-rays to ultra-lengthy wavelength radio waves, and everything that comes in between. However, the peak of the emission takes place in the visible part of the spectrum.

HELP ASAPFor the reaction A(g) → 2B(g), Keq = 4.5 × 105. Which statement is true for the system at equilibrium?
a) [A] >> [B]
b)Changing the temperature will have no affect on the equilibrium.
c)There is twice as much A as there is B in the reaction vessel.
d)There is more than 100 times more B then there is A in the reaction vessel.
e)There is twice as much B as there is A in the reaction vessel.

Answers

The correct answer for the question that is being presented above is this one: "d)There is more than 100 times more B then there is A in the reaction vessel." The statement is true for the system at equilibrium is that d)There is more than 100 times more B then there is A in the reaction vessel.

a compound consists of 17.6% of hydrogen and 82.4% nitrogen. Determine the empirical formula of the compound

Answers

Answer: The empirical formula for the given compound is $NH_3$

Explanation:

We are given:

Percentage of H = 17.6 %

Percentage of N = 82.4 %

Let the mass of compound be 100 g. So, percentages given are taken as mass.

Mass of H = 17.6 g

Mass of N = 82.4 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=(17.6g)/(1g/mole)=17.6moles$

Moles of Nitrogen = $\frac{\text{Given mass of nitrogen}}{\text{Molar mass of nitrogen}}=(82.4g)/(14g/mole)=5.88moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 5.88 moles.

For Hydrogen = $(17.6)/(5.88)=2.99\approx 3$

For Nitrogen = $(5.88)/(5.88)=1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of H : N = 3 : 1

Hence, the empirical formula for the given compound is $NH_3$

17,6% + 82,6% = 100%

mass of N = 14g
mass of H = 1g

17,6% H = 17,6g H
82,4% N = 82,4g N

17,6g : 1g = 17,6 moles of H
82,4g : 14g = 5,89 moles of N

N : H = 5,89 : 17,6 ||:5,89
N : H = 1 : 2,99≈3

the empirical formula of the compound = NH₃ (ammonia)

In the following electrochemical cell, what is the reduction half-reaction? Mn(s) | Mn2+(aq) || Fe3+(aq), Fe2+(aq) | Pt(s)

Answers

In the given electrochemical cell, the reduction half-reaction occurs at the electrode on the right side of the double vertical line (||).

To determine the reduction half-reaction, we need to compare the standard reduction potentials (E°) of the species involved. The half-reaction with the more positive E° value will be the reduction half-reaction.

Looking up the standard reduction potentials in a reference table, we find that the standard reduction potential for the Mn2+/Mn couple is -1.18 V, and the standard reduction potential for the Fe3+/Fe2+ couple is +0.77 V.

Since the Fe3+/Fe2+ couple has a more positive standard reduction potential, it will undergo reduction. Therefore, the reduction half-reaction is:

Fe3+(aq) + e- → Fe2+(aq)

I hope this helps!

How many meters in 1000 mm

Answers

1000 mm equals 1 meter

1000 mm equals 1 meter.

A solution is highly concentrated if there is:a large volume of solution

a large amount of solvent and a small amount of solute

a large amount of solute and a small amount of solvent

a high density value for the solution

Answers

TO be saturated you need an amount of solvent that will not dissolve anymore into the solution. So, the best answer from the list is C

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