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2 years ago

Which best protects animal species that are endangered due to overhunting?

Chemistry

2 answers:

Mekhanik [1.2K]2 years ago

7 0

Answer:

captive breeding would help the best

Naddika [18.5K]2 years ago

5 0

Answer:

poaching

Explanation:

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Suppose a group of volunteers is planning to build a park near a local lake. The lake is known to contain low levels of arsenic

Kisachek [45]

Answer:

A) 10.75 is the concentration of arsenic in the sample in parts per billion .

B) 7,633.66 kg the total mass of arsenic in the lake that the company have to remove.

C) It will take 1.37 years to remove all of the arsenic from the lake.

Explanation:

A) Mass of arsenic in lake water sample = 164.5 ng

The ppb is the amount of solute (in micrograms) present in kilogram of a solvent. It is also known as parts-per million.

To calculate the ppm of oxygen in sea water, we use the equation:

$\text{ppb}=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 10^9$

Both the masses are in grams.

We are given:

Mass of arsenic = 164.5 ng = $164.5\times 10^{-9} g$

$1 ng=10^{-9} g$

Volume of the sample = V = $15.3 cm^3$

Density of the lake water sample ,d= $1.00 g/cm^3$

Mass of sample = M = $d\times V=1.0 g/cm^3\times 15.3 cm^3=15.3 g$

$ppb=\frac{164.5\times 10^{-9} g}{15.3 g}\times 10^9=10.75$

10.75 is the concentration of arsenic in the sample in parts per billion.

Mass of arsenic in $1 cm^3$ of lake water = $\frac{164.5\times 10^{-9} g}{15.3}=1.075\times 10^{-8} g$

Mass of arsenic in $0.710 km^3$ lake water be m.

$1 km^3=10^{15} cm^3$

Mass of arsenic in $0.710\times 10^{15} cm^3$ lake water :

$m=0.710\times 10^{15}\times 1.075\times 10^{-8} g=7,633,660.130 g$

1 g = 0.001 kg

7,633,660.130 g = 7,633,660.130 × 0.001 kg=7,633.660130 kg ≈ 7,633.66 kg

7,633.66 kg the total mass of arsenic in the lake that the company have to remove.

Company claims that it takes 2.74 days to remove 41.90 kilogram of arsenic from lake water.

Days required to remove 1 kilogram of arsenic from the lake water :

$\frac{2.74}{41.90} days$

Then days required to remove 7,633.66 kg of arsenic from the lake water :

$=7,633.66\times \frac{2.74}{41.90} days=499.19 days$

1 year = 365 days

499.19 days = $\frac{499.19}{365} years = 1.367 years\approx 1.37 years$

It will take 1.37 years to remove all of the arsenic from the lake.

3 0

2 years ago

When balanced, which equation would have the coefficient 3 in front of any of the reactants? Zn + HCl ZnCl2 + H2 H2SO4 + B(OH)3

Gwar [14]

The correct answer is B. H2SO4 + B(OH)3 B2(SO4)3 + H2O

Hope this helps!

6 0

2 years ago

Read 2 more answers

A copper rod that has a mass of 200.0 g has an initial temperature of 20.0°C and is heated to 40.0°C. If 1,540 J of heat are nee

Romashka [77]

Heat gained in a system can be calculated by multiplying the given mass to the specific heat capacity of the substance and the temperature difference. It is expressed as follows:

Heat = mC(T2-T1)

1540 = 200.0 (C)(40 - 20)

C = 0.385 J / g C

Hope this answers the question. Have a nice day.

8 0

2 years ago

Read 2 more answers

HIPVs can cause what two more severe illnesses?

Nat2105 [25]

One of them are Cancer

4 0

2 years ago

Which of the following pairs of compounds would be most easily separated by thin layer chromatography: n-octyl alcohol and 1-oct

vivado [14]

Answer:

B. n-octyl alcohol and 1-octene

Explanation:

Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. The principle is that different compounds in the sample mixture travel at different rates due to the differences in interactions with stationary phase and due to the differences in solubility in the solvent. The principal chemical property for separation using this technique is molecular polarity

You can intuit than hexadecane and octadecane don't have big polarity differences, also chlorobenzene and bromobenzene haven't.

An alcohol as n-octyl alcohol has different polarity than an alkene as 1-octene.

Thus, using thin layer chromatography is most easy to separate:

B. n-octyl alcohol and 1-octene

I hope it helps!

8 0

2 years ago