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2 years ago

In fossil comparisons, it helps to know about similar:

Chemistry

1 answer:

omeli [17]2 years ago

6 0

Answer:

Fossils tell us when organisms lived, as well as provide evidence for the Fossils are the preserved remains or traces of animals, plants, and other organisms from the past. Fossils, by comparing the anatomies of both modern and extinct species, allows scientists to study the skin, hair, and organs of ancient creatures.

Explanation:

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Why do sea and ocean levels recede (more coast land is exposed) when the planet goes through a major ice age?

fomenos

This happens because ice is made up of water, and when that water freezes, it never goes back to land, thus there being less water on the coastline. But when the ice starts to melt, the water will even out quickly, and the water will go to the coastline, causing the tide to rise. Mark brainliest, please.

3 0

3 years ago

How many atoms are in 25.00 g of B.

iren2701 [21]

Answer:

$\boxed {\boxed {\sf 1.393 *10^{24} \ atoms \ B}}$

Explanation:

<u>1. Convert Grams to Moles</u>

Use the molar mass (found on the Periodic Table) to convert from grams to moles.

Boron (B): 10.81 g/mol

Use this value as a ratio.

$\frac {10.81 \ g \ B }{1 \ mol \ B}$

Multiply by the given number of grams.

$25.00 \ g \ B *\frac {10.81 \ g \ B }{1 \ mol \ B}$

Flip the ratio so the grams of boron cancel out.

$25.00 \ g \ B *\frac {1 \ mol \ B }{10.81 \ g \ B}$

$25.00 *\frac {1 \ mol \ B }{10.81 }$

$\frac {25.00 \ mol \ B }{10.81 }=2.312673451 \ mol \ B$

<u>2. Convert Moles to Atoms</u>

We use Avogadro's Number, 6.02*10²³: the number of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case, the particles are atoms of boron.

$\frac {6.02*10^{23} \ atoms \ B} {1 \ mol \ B}$

Multiply by the number of moles we calculated.

$2.312673451 \ mol \ B *\frac {6.02*10^{23} \ atoms \ B} {1 \ mol \ B}$

The moles of boron cancel.

$2.312673451 *\frac {6.02*10^{23} \ atoms \ B} {1 }$

$2.312673451 *6.02*10^{23} \ atoms \ B} =1.39269195*10^{24} \ atoms \ B$

The original value of grams has 4 significant figures, so our answer should have the same. For the number we calculated, that is the thousandth place.

$1.392\underline69195*10^{24} \ atoms \ B$

The 6 tells us to round the 2 to a 3.

$1.393 *10^{24} \ atoms \ B$

25.00 grams of boron is equal to 1.393*10²⁴ atoms.

6 0

3 years ago

If a mineral has a metallic shine and scratches, which of its properties are being measured? Choose the two correct answers.

zzz [600]

If a mineral has a metallic shine and scratches, which of its properties are being measured?
Choose the two correct answers.

magnetism

hardness

cleavage

luster

Answer: hardness and luster

8 0

3 years ago

Which shows the general structure of a carboxylic acid

taurus [48]

Answer:b

Explanation:

I just did it

3 0

3 years ago

State Henry's law. Give an example of Henry's law.

ruslelena [56]

Answer:

Found this off of google, "Henry's law comes into play every time a bottle of Pepsi (or any other carbonated drink) is opened. The gas above the unopened carbonated drink is usually pure carbon dioxide, kept at a pressure which is slightly above the standard atmospheric pressure."

4 0

3 years ago