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6 days ago

In 1906, there was a small population of deer on the Kaibab Plateau. Because cows had overgrazed the food on the Kaibab Plateau,

the Forest Service decided to create a preserve on the Kaibab Plateau for the deer. In the preserve, the cows and the natural predators of the deer were removed. In 1920, the Forest Service discovered that the number of deer in the preserve was very large. By 1923, most of the deer were starving from a lack of food. Which statement best describes what happened on the Kaibab Plateau between 1906 and 1923? Overgrazing by cows caused the deer on the Kaibab Plateau to starve. The large growth and starvation of the deer population was an event of natural selection. With no natural predators to regulate the population, the deer population continued to grow. The growth of the deer population was slower than the growth of the food supply on the Plateau, causing starvation.

Chemistry

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You want to prepare a solution with a concentration of 200.0μM from a stock solution with a concentration of 500.0mM. At your di

lorasvet [2795]

Answer:

1) This dilution plan will yield a 200μM solution.

2) This dilution plan will not yield a 200μM solution.

3) This dilution plan will not yield a 200μM solution.

4) This dilution plan will yield a 200μM solution.

5) This dilution plan will yield a 200μM solution.

Explanation:

Convert the initial molarity into molar form as shown.

$500mM = 500mM \times (\frac{1M}{1000M})= 0.5M$

Let's examine the following serial dilution processes.

Dilute 5.00 mL of the stock solution to 500 mL. Then take 10.00 mL of this new solution and dilute it further to 250 mL.

Concentration of 500 mL solution:

$M_{2}= \frac{M_{1}V_{1}}{V_{2}}= \frac{(0.5M)(5.00mL)}{500 mL}= 5 \times 10^{-3}M$

10 mL of this solution is further diluted to 250 mL

$M_{final}= \frac{M_{2}V_{2}}{V_{final}}= \frac{(5 \times 10^{-3}M)(10.0mL)}{250 mL}= 2 \times 10^{-4}M$

Convert μM:

$2 \times 10^{-4}M = (2 \times 10^{-4}M)(\frac{1 \mu M}{10^{-6}M})= 200 \mu M$

Thus, this dilution scheme will yield a 200μM solution.

Dilute 5.00 mL of the stock solution to 100 mL. Then take 10.00 mL of this new solution and dilute to 1000 mL.

Concentration of 100 mL solution:

$M_{2}= \frac{M_{1}V_{1}}{V_{2}}= \frac{(0.5M)(5.00mL)}{100 mL}= 2.5 \times 10^{-2}M$

10 mL of this solution is further diluted to 1000 mL

$M_{final}= \frac{M_{2}V_{2}}{V_{final}}= \frac{(2.5 \times 10^{-2}M)(10.0mL)}{1000 mL}= 2.5 \times 10^{-4}M$

Convert μM:

$2.5 \times 10^{-4}M = (2.5 \times 10^{-4}M)(\frac{1 \mu M}{10^{-6}M})= 250 \mu M$

Thus, this dilution scheme will not yield a 200μM solution.

Dilute 10.00 mL of the stock solution to 100 mL, followed by diluting 5 mL of that new solution to 100 mL.

Concentration of 100 mL solution:

$M_{2}= \frac{M_{1}V_{1}}{V_{2}}= \frac{(0.5M)(10mL)}{100 mL}= 0.05M$

5 mL of this solution is diluted to 1000 mL

$M_{final}= \frac{M_{2}V_{2}}{V_{final}}= \frac{(0.05M)(5mL)}{1000 mL}= 0.25 \times 10^{-4}M$

Convert μM:

$0.25 \times 10^{-4}M = (0.25 \times 10^{-4}M)(\frac{1 \mu M}{10^{-6}M})= 25 \mu M$

Thus, this dilution scheme will not yield a 200μM solution.

Dilute 5 mL of the stock solution to 250 mL. Then take 10 mL of this new solution and further dilute it to 500 mL.

Concentration of 250 mL solution:

$M_{2}= \frac{M_{1}V_{1}}{V_{2}}= \frac{(0.5M)(5mL)}{250 mL}= 0.01M$

10 mL of this solution is further diluted to 500 mL

$M_{final}= \frac{M_{2}V_{2}}{V_{final}}= \frac{(0.01M)(10mL)}{500 mL}= 2 \times 10^{-4}M$

Convert μM:

$2 \times 10^{-4}M = (2 \times 10^{-4}M)(\frac{1 \mu M}{10^{-6}M})= 200 \mu M$

Thus, this dilution scheme will yield a 200μM solution.

Dilute 10 mL of the stock solution to 250 mL. Then take another 10 mL of this new solution and dilute it to 1000 mL.

Concentration of 250 mL solution:

$M_{2}= \frac{M_{1}V_{1}}{V_{2}}= \frac{(0.5M)(10mL)}{250 mL}= 0.02M$

10 mL of this solution is further diluted to 1000 mL

$M_{final}= \frac{M_{2}V_{2}}{V_{final}}= \frac{(0.02M)(10mL)}{1000 mL}= 2 \times 10^{-4}M$

Convert μM:

$2 \times 10^{-4}M = (2 \times 10^{-4}M)(\frac{1 \mu M}{10^{-6}M})= 200 \mu M$

Thus, this dilution scheme will yield a 200μM solution.

7 0

3 months ago

which intensive physical property is observed when droppings of a person seated inside a closed room has able to reach a person

lions [2927]

Answer:

The correct answer is "Speed".

Explanation:

An intensive or individualized physical property is identified when "speed" is observed as the excretion of an individual in a confined area, capable of reaching someone one meter away after sneezing or coughing.
This measure is represented in the unit of "meter per second", indicating its intensive nature.

5 0

4 months ago

Several amino acids are intermediates of the urea cycle, having side ammonia groups that join with free carbon dioxide (CO2) and

Alekssandra [3086]

Response:

A. Arginine

Clarification:

The urea cycle consists of biochemical processes that convert ammonia into urea.

Steps of the urea cycle:

Carbamoyl phosphate reacts with ornithine transcarbamoylase to form citrulline through the release of a phosphate group along with ornithine.
In the presence of argininosuccinate synthetase, the amino group from aspartate and the carbonyl from citrulline combine to create argininosuccinate. This reaction requires ATP.
Subsequently, argininosuccinate is split by argininosuccinase to yield arginine and fumarate.
Then, arginine is broken down by arginase to produce urea and ornithine. Ornithine is recycled back to mitochondria, restarting the urea cycle.

7 0

3 months ago