answer.
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
Snezhnost [94]
1 year ago
15

The isotope radium-226 decays into radon-222, with a half-life of around 1,600 years. If a rock contained 6 grams of radium-226

when it reached its closure temperature but only 0.375 grams when it was discovered, which two statements about the rock are true?
A] The rock reached its closure temperature 6,400 years ago.
B] The rock reached its closure temperature 4,800 years ago.
C]The rock had 2.625 grams of radon-222 1,600 years ago.
D]When the rock was discovered, it had 5.625 grams of radon-222.
E]When the rock was discovered, it had 3.375 grams of radon-222.
Biology
2 answers:
inysia [295]1 year ago
5 0
A and D is the answer
sveticcg [70]1 year ago
5 0

Answer : The correct option is, (A) The rock reached its closure temperature 6,400 years ago.

Explanation :

Half-life = 1600 years

First we have to calculate the rate constant, we use the formula :

k=\frac{0.693}{t_{1/2}}

k=\frac{0.693}{1600\text{ years}}

k=4.33\times 10^{-4}\text{ years}^{-1}

Now we have to calculate the time passed.

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant  = 4.33\times 10^{-4}\text{ years}^{-1}

t = time passed by the sample  = ?

a = initial amount of the reactant  = 6 g

a - x = amount left after decay process = 0.375 g

Now put all the given values in above equation, we get

t=\frac{2.303}{4.33\times 10^{-4}}\log\frac{6}{0.375}

t=6404.36\text{ years}\approx 6400\text{ years}

Therefore, the correct option is, (A) The rock reached its closure temperature 6,400 years ago.

You might be interested in
One of the first Mendelian traits identified in humans was a dominant condition known as brachydactyly. This gene causes an abno
kvv77 [185]

Answer:

The correct option is C. Rare alleles tend to remain rare even when they are dominant.The distribution of a gene among individuals is determined by mating and environmental factors.

Explanation:

Most people believe that a rare allele would only be recessive. But this is not correct. A rare allele can be dominant. The frequency of an allele to occur in a population will depend on the environmental factors. The alleles which code for traits that are best suitable for living in an environment will be seen in more abundance. The frequency of an allele to occur in a population also depends on the breeding trends of the population.

5 0
1 year ago
A benefit of monoculture farming practices is what?
katen-ka-za [31]

The main benefits of the monoculture farming are that it has higher production, is more efficient, and has lower costs. All three advantages of the monoculture farming are making it much more attractive for the farmers as it is more profitable and easier for work.

In this type of farming there's no spaces of the arable land that are lost because it is all planted with the same culture, and there isn't any other cultures with which there should be made empty spaces in between.

The costs for farming are lower, and also the work is easier and more efficient because the machinery can be used in the same manner constantly and the work can go on systematically on the farmlands.

On the other hand, we have to mention that there are also negative effects of this type of farming like the total destruction of animal and plant biodiversity in the area where it is practiced, as well as making the entire crop vulnerable to diseases and environmental changes.

4 0
1 year ago
The microtubules in the cell membrane are like the skeletal and muscular system because?​
USPshnik [31]

Answer:

They are major components of the cytoskeleton

Explanation:

They are found in all eukaryotic cells and are involved in mitosis , cell motility, intracellular transport and maintanance of cell shape

7 0
1 year ago
Which type of sentence is this? Astronauts can experience bone loss, muscle weakness, and diminished heart function when they ar
sergey [27]
The simple is the best answer for this question
3 0
1 year ago
Read 2 more answers
Working from deep geologic strata toward shallow geologic strata, what is the sequence in which fossils of these groups should m
pentagon [3]

Answer:

1. charophytes

Explanation:

  • These are macrophytes that grow entire in the freshwater and become fossilized by the calcification oozes,  going back to the Paleozoic era about 250 million years ago.
  • And they are unicellular to multi-cellular organisms also found in moist terrestrial habitats.
4 0
1 year ago
Other questions:
  • Vestibular information travels to all of the following areas of the brain except the __________. medulla pons cerebellum optic c
    14·2 answers
  • A traditional facial reconstruction uses what material?
    11·1 answer
  • Match each example to the correct dimension of wellness. not all dimensions will have the same number of examples.
    13·1 answer
  • Complete hydrolysis of a glycerophospholipid yields glycerol, two fatty acids (18:2(δ9,12) and 18:0), phosphoric acid, and choli
    12·2 answers
  • The rough endoplasmic reticulum is a cell structure that consists of folded membranes that contain ribosomes. What is the advant
    8·1 answer
  • As part of their normal function, many proteins bind to DNA briefly and then release it again. Which types of interactions might
    15·1 answer
  • Use the drop-down menus to order the steps involved in protein production.
    14·2 answers
  • Some mammals such as Moose, Deer, and Water Buffalos have defensive adaptations such as horns or antlers to fight predators. Mal
    12·1 answer
  • Which category of environmental worldview do you think would be most likely to lead to a sustainable future if it were widely ac
    15·1 answer
  • A part of the Calvin cycle has been removed from the diagram on the right. What occurs at this stage of the cycle? Carbon fixati
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!