1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
arlik [135]
3 years ago
15

Use the References to access important values if needed for this question. Radioactive decay can be described by the following e

quation where is the original amount of the substance, is the amount of the substance remaining after time , and is a constant that is characteristic of the substance. For the radioactive isotope iron-55, is . If the original amount of iron-55 in a sample is 74.0 mg, how much time is needed for the amount of iron-55 that remains to fall to 32.7 mg? years
Chemistry
1 answer:
zalisa [80]3 years ago
3 0

Answer:

Explanation:

  • from the Radioactive decay equation ; lnA = ln Ao - kt
  • Ao = original amount of substance = 74mg
  • where A = is the amount of the substance remaining after time t = 32.7mg,
  • k = is a constant that is characteristic of the substance = 2.67 x 10^-1 years^-1
  • t = ?

All radioactive substances follow the first order kinetics, as such the rate constant for first order is given as , k = 1/t ln[Ao/A]

  • hence t = 1/k ln[Ao/A]
  • plugging the values in the equation;
  • t = 1/0.267 x ln [74/32.7]
  • t = 3.745 ln(2.2629)
  • t = 3.05years is the time needed

You might be interested in
Which of the following represents a compound? C20 H2O O2 H2
Andre45 [30]
The answer is C2O.............
7 0
3 years ago
Read 2 more answers
In each case, calculate the appropriate ratio to show that the information given is consistent with the law of multiple proporti
Alchen [17]

Answer:

(a) 3:2; (b) 2:1

Explanation:

The Law of Multiple Proportions states that when two elements A and B combine to form two or more compounds, the masses of B that combine with a given mass of A are in the ratios of small whole numbers.

That is, if one compound has a ratio r₁ and the other has a ratio r₂, the ratio of the ratios r is in small whole numbers.

(a) Ammonia and hydrazine.

In ammonia, the mass ratio of H:N is r₁ = 0.2158/1

In hydrazine, the mass ratio of H:N is r₂ = 0.1439/1

The ratio of the ratios is:

r = \dfrac{r_{1}}{r_{2}} = \dfrac{ 0.2158}{0.1439} = \dfrac{1.500 }{1} = \dfrac{2.999}{2} \approx \mathbf{\dfrac{3}{2}}\\\\\text{The relative amounts of H in the two compounds are in the ratio }\boxed{\mathbf{\dfrac{3}{2}}}

(b) Nitrogen oxides

In nitrogen monoxide, the mass ratio of O:N is r₁ = 1.142/1

In dinitrogen monoxide, the mass ratio of O:N is r₂ = 0.571/1

The ratio of the ratios is:

r = \dfrac{r_{1}}{r_{2}} = \dfrac{ 1.142}{0.571} = \dfrac{2.000 }{1} \approx \mathbf{\dfrac{2}{1}}\\\\\text{The relative amounts of O in the two compounds are in the ratio }\boxed{\mathbf{\dfrac{2}{1}}}

8 0
4 years ago
Transuranium elements are artificial and may be prepared by a fusion process in which heavy nuclei are bombarded with light ones
Scilla [17]

Answer:

_{97}^{345}\textrm{Bk}

Explanation:

In a nuclear reaction, the total mass and total atomic number remains the same.

Am has an atomic number of 95. So correct reaction is:-

^{343}_{95}\textrm{Am}+^{4}_{2}\textrm{He}\rightarrow ^A_Z\textrm{X}+2^1_0\textrm{n}

To calculate A:

Total mass on reactant side = total mass on product side

343 + 4 = A + 2

A = 345

To calculate Z:

Total atomic number on reactant side = total atomic number on product side

95 + 2 = Z + 0

Z = 97

Hence, the isotopic symbol of unknown element is _{97}^{345}\textrm{Bk}

7 0
3 years ago
Prandtl number in heat transfer analogues to which dimension less number in mass transfer. a) Schmidt number b) Sherwood number
Cloud [144]

Answer:

a) Schmidt number

Explanation:

Prandtl number in heat transfer is analogues to Schmidt number in mass transfer.

Prandtl number in heat transfer is the ration of momentum diffusivity to the heat diffusivity.

P_r = \frac{\nu}{\alpha}

Whereas, Schmidt number in mass transfer is the ratio of momentum diffusivity to the mass diffusivity.

S_c= \frac{\nu}{\nu_{AB}}

5 0
3 years ago
Please help I am stuck
Ksenya-84 [330]
The theory of plate tectonics tells exactly where the continents were before Pangaea divided.

I'm not a 100% sure but I feel strong about is
8 0
3 years ago
Other questions:
  • Describes how Anders Celsius devised the temperature scale that bears his name
    8·1 answer
  • If a sample of oxygen occupies a volume of 2.15 L at a pressure of 58.0 kPa and a temperature of 25°C, what volume would this sa
    8·1 answer
  • PAP Physical Studies<br><br> How can you remember the periodic table?
    7·2 answers
  • Combustion of hydrocarbons such as nonane () produces carbon dioxide, a "greenhouse gas." Greenhouse gases in the Earth's atmosp
    8·1 answer
  • 3) Summarize the ways the desert can help preserve a body.
    13·1 answer
  • How can scientists determine when a radioactive substance will no longer be dangerous
    5·1 answer
  • A chemist measures the amount of bromine liquid produced during an experiment. She finds that 14.4 g of bromine liquid is produc
    9·1 answer
  • Newton's first law of motion says that an object in motion will remain in
    7·1 answer
  • How much work is done on a pumpkin with a force of 16 newtons when you lift is 15 meters?
    10·1 answer
  • A 25. 0-ml sample of 0. 150 m hydrocyanic acid is titrated with a 0. 150 m naoh solution. What is the ph beforeany base is added
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!