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2 years ago

12

How have organisms changed over time, according to the fossil record?

1 answer:

Yuri [45]2 years ago

6 0

Answer:

As the world changes, plants and animals change with it. Aside from a few living fossils, the species we see today are very different from species that lived in the past. Thus, the fossil record can be used to show that organisms changed to meet new conditions. This is the result of evolution of species over time.

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Explanation:

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If not managed properly, aquaculture can

Damm [24]

C. pollute water and damage aquatic ecosystems

7 0

3 years ago

Please help I'm not good at science

Citrus2011 [14]

Answer:

i'm not able to see images but if you type it all i can answer:)

Explanation:

8 0

3 years ago

An interpenetrating primitive cubic structure like that of CsCl with anions in the corners has an edge length of 664 pm. If the

san4es73 [151]

Answer:

the ionic radius of the anion $r^- = 312.52 \ pm$

Explanation:

From the diagram shown below :

The anion $Cl^-$ is located at the corners

The cation $Cs^+$ is located at the body center

The Body diagonal length = $\sqrt{3 \ a }$

∴ $2 \ r^+ \ + 2r^- \ = \sqrt{3 \ a} \\ \\ r^+ +r^- = \frac{\sqrt{3}}{2} a$

Given that :

$\frac{r^+}{r^-} =0.84$ (i.e the ratio of the ionic radius of the cation to the ionic radius of

the anion )

$0.84r^- \ + r^- \ = \frac{\sqrt{3}}{2}a \\ \\ 1.84 r^- = \frac{3}{2}a \\ \\ r^- = \frac{\sqrt{3}}{2*1.84}a$

Also ; a = 664 pm

Then :

$r^- = \frac{\sqrt{3} }{2*1.84}*664 \ pm\\ \\ r^- = 312.52 \ pm$

Therefore, the ionic radius of the anion $r^- = 312.52 \ pm$

4 0

3 years ago

HELPPP!!! what is the volume (in liters) of a 5.72 gram sample of 02 at STP? (Hint: remember to change grams of oxygen to moles

Alona [7]

Answer:

4L

Explanation:

To obtain the volume of O2 at stp, first, we need to determine the number of mole of O2.

From the question given above,

Mass of O2 = 5.72g

Molar Mass of O2 = 32g/mol

Number of mole =Mass/Molar Mass

Number of mole of O2 = 5.72/32

Number of mole of O2 = 0.179 mole

Now, we can calculate the volume of O2 at stp as follow:

1 mole of a gas occupy 22.4L at stp.

Therefore, 0.179 mole of O2 will occupy = 0.179 x 22.4 = 4L

Therefore, the volume occupied by the sample of O2 is 4L

7 0

3 years ago

Sodium hydride racts with excess water to produce

romanna [79]

Answer:

0.96g of sodium hydride

Explanation:

Equation of reaction:

NaH + H20 = NaOH + H2

Mass of hydrogen gas produced (m) = PVM/RT

P = 765torr - 28torr = 737torr = 737/760 = 0.97atm, V = 982mL = 982cm^3, M = 2g/mol, R = 82.057cm^3.atm/gmol.K, T = 28°C = 28 + 273K = 301K

m = (0.97×982×2)/(82.057×301) = 0.08g of hydrogen gas

From the equation of reaction

1 mole (24g) of sodium hydride produced 1 mole (2g) of hydrogen gas

0.08g of hydrogen gas would be produced by (24×0.08)/2 = 0.96g of sodium hydride

8 0

3 years ago