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
8090 [49]
2 years ago
8

Iron-55 has a half-life of 3 years. How much of a 40 gram sample will remain after 12 years? A. 0 grams B. 4 grams C. 2.5 grams

D. 20 grams
Biology
1 answer:
Readme [11.4K]2 years ago
4 0

Answer:

\boxed {\boxed {\sf C. \ 2.5 \ grams }}

Explanation:

We are asked to find how much of a 40 gram sample remains after 12 years.

Iron-55 has a half-life of 3 years. Therefore, after 12 years, 4 half-lives have been completed.

  • 12 years/3 years = 4 half-lives

Every time a half-life is completed, half of the sample's mass decays. Remember we start with a 40 gram sample.

  • 1 half- life: 40 g / 2 = 20 g
  • 2 half-lives: 20 g / 2= 10 g
  • 3 half-lives: 10 g / 2 = 5 g
  • 4 half-lives: 5 g / 2 = 2.5 g

There is also a formula that can be used to solve this problem.

A= A_o(\frac {1}{2})^{\frac{t}{hl}

Where A₀ is the initial amount, t is the time, and hl is the half-life.

We know 40 grams is the inital amount, 12 years is the time, and 3 years is the halflife.

  • A₀= 40 g
  • t= 12
  • hl= 3

A= 40 \ g (\frac{1}{2})^\frac{12}{3}

A= 40 \ g (\frac{1}{2})^4

A= 40 \ g * 0.0625

\bold {A= 2.5 \ g}

After 12 years, <u>2.5 grams </u> of Iron-55 will remain.

You might be interested in
1. What molecule carries chemical energy that cells use for their functions?
Assoli18 [71]

Answer:

adenosine triphosphate

Explanation:

Your energy does come from food, but not directly. All cells, like that in Figure 1.1, use chemical energy carried by ATP— adenosine triphosphate. ATP is a molecule that transfers energy from the breakdown of food molecules to cell processes.

8 0
2 years ago
The measurement of the amount of water vapor in the air called
Yuri [45]
Humidity. I think you need to work on your grammar a little bit pal, if you ever need help with ELA homework, hmu.
4 0
3 years ago
Read 2 more answers
Which is the correct path of blood flow?
Nana76 [90]

Answer:

Body

— Right atrium Right ventricle - Lungs – Left atrium Left ventricle -

Explanation:

3 0
3 years ago
Why is taxonomy important to scientists?
chubhunter [2.5K]
It helps us categorize organisms so we can more easily communicate biological information. Taxonomy uses hierarchical classification as a way to help scientists understand and organize the diversity of life on our planet.
6 0
2 years ago
Read 2 more answers
Are plants able to do cellular respiration? Why or why not?
Maru [420]

Both plants and animals are able to do cellular respiration. Plants convert nutrients from the soil into usable energy.

This is the plant cellular respiration formula:

oxygen + glucose -> carbon dioxide + water + heat energy

Hope this helped! Let me know if there is anything I need to clarify or explain more in depth

8 0
3 years ago
Other questions:
  • The main difference between a taproot system and a fibrous root system
    9·1 answer
  • Why do you think forensic scientists study bloodstain patterns? What can be learned from them?
    13·1 answer
  • a hypothetical cell has approximate shape of a shape of a sphere. rhw diameter of thw spherical cell os six units long. another
    13·1 answer
  • In Mendel’s pea plant experiments, which term best describes the white flower trait that is masked by the purple flower trait?
    9·1 answer
  • What is not an impact to ecosystems during a drought
    13·1 answer
  • In what ways are the respiratory structures of all animals similar?
    10·1 answer
  • In peas, axial (A) flower position is dominant to terminal (a), tall (L) is dominant to short (l), and yellow (Y) is dominant to
    14·1 answer
  • Hey ! what is the difference between a habitat and a niche?
    5·2 answers
  • Bacteria do not contain a nucleus. Explain how they can function without it.
    15·1 answer
  • Fracking is a way to obtain oil and natural gas trapped in rock. during
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!