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Otrada [13]
2 years ago
5

Iron-59 is used in medicine to diagnose blood circulation disorders. The half life of iron-59 is 44.5 days. How much of a 2.000

mg sample will remain after 133.5 days? Show your work
Chemistry
1 answer:
kolezko [41]2 years ago
7 0

Answer:

0.258 mg of iron remains.

Explanation:

To solve this problem we can use the formula

M₂ = M₀ * 0.5^{\frac{t}{44.5} }

Where M₂ is the mass remaining, M₀ is the initial mass, and t is time in days.

Using the data given by the problem:

M₂ = 2.000 mg * 0.5^{\frac{133.5}{44.5} }

M₂ = 0.258 mg

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Sara tells Michael she is 160 centimeters tall, while Michael says he is 60 inches tall. If there are 2.54 centimeters in an inc
makvit [3.9K]
Sara is taller. 160cm =160 cm while to convert inches to centimeters you just multiply. 60 x 2.54 = 152.4cm which is less than 160 so sara is taller.
4 0
2 years ago
A molecular biologist measures the mass of cofactor a in an average yeast cell. the mass is 41.5 pg . what is the total mass in
Ronch [10]
In this question, you are given the average cofactor mass per cell (41.5pg) and the total cells count(105 cells). You are asked how much cofactor that will be found from those cells(microgram= 10^6 picogram). Then the calculation would be:
Cofactor mass= cofactor per cell * cell count= 41.5pg/cell * 105 cells= 4357.5pg= 4.36 x 10^3pg

Then convert the picogram(pg) into microgram: 4.36 x 10^3pg/ (10^6pg/microgram)= 4.36x10^-3 microgram or 0.00436 microgram

if 105 cells mean 10^5 cells, the answer should be 4.15 microgram
6 0
2 years ago
Read 2 more answers
What is the pH of a solution prepared by mixing 50.00 mL of 0.10 M methylamine, CH3NH2, with 20.00 mL of 0.10 M methylammonium c
olya-2409 [2.1K]

Answer:

pH=10.97

Explanation:

the solution of methyl amine with methylammonium chloride will make a buffer solution.

The pH of buffer solution can be obtained using Henderson Hassalbalch's equation, which is:

pOH=pKb+log\frac{[salt]}{[base]}

pH = 14- pOH

Let us calculate pOHpOH=3.43+ (-0.397)=3.03

pH=14-pOH=14-3.03=10.97

[Salt] = [methylammonium chloride] = 0.10 M (initial)

After adding base

[salt] = \frac{molarityXvolume}{finalvolume}=\frac{0.1X20}{(20+50)}= 0.0286M

[base] = [Methylamine]=0.10

After mixing with salt

[base]= \frac{molarityXvolume}{finalvolume}=\frac{0.1X50}{(20+50)}= 0.0714M

pKb= -log[Kb]= 3.43

Putting values

pOH = 3.43+log(\frac{[0.0286]}{0.0714}

4 0
2 years ago
Which of the following organisms are carnivores?
sineoko [7]

Answer:

Secondary consumers

Explanation:

Carnivores are organisms that only eat meat and that rely on others for food and energy; this means that they cannot produce food themselves.

Look at the answer choices:

- Decomposers: these are organisms that break down dead matter into material that can be used later by plants to grow; carnivores do not break down dead matter; rather, they eat meat.

- Primary consumers: these are usually herbivores; they are the second level of the energy pyramid, and they eat the organisms at the bottom level. The organisms at the bottom level are plants that make their own food. Obviously, plants are not meat, so carnivores are not primary consumers.

- Producers: these are the plants at the bottom of the energy pyramid that make their own food. Carnivores do not make their own food.

Thus, the answer is secondary consumers because this level of organisms eat the organisms at the primary consumer level.

Hope this helps!

5 0
2 years ago
Which of these tasks falls under the responsibility of a forensic scientist?
Varvara68 [4.7K]

Answer:

Training officers in how to properly collect evidence

Explanation:

Forensic science is an interesting branch of science that involves the use of scientific procedures to solve a crime case. It encompasses collection of physical evidence from the crime scene and analyzing it in a laboratory using scientific means.

A forensic scientist is the individual in charge of performing these scientific procedures. His/her major role is to run the scientific analysis of the physical evidence brought in by the officers, however, he/she can also perform the task of training officers in how to properly collect evidence, in order not to damage the evidence or render it invalid for use.

8 0
2 years ago
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