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3 years ago

Does the fossil record include every species that every lived? Why or why not?

Chemistry

1 answer:

fgiga [73]3 years ago

3 0

No, some species didn’t have bones and things of the such that could become fossilized.

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How many molecules of ethanol (c2h5oh) (the alcohol in alcoholic beverages) are present in 140 ml of ethanol? the density of eth

Bond [772]

An mL is also equivalent to cm³, signifying that 140 mL is equivalent to 140 cm³. The mass of ethanol is calculated by multiplying the density by the volume.

mass = (140 cm³)(0.789 g/cm³)
mass = 110.46 g

Then, calculate the number of moles of ethanol by dividing the mass by the molar mass of ethanol equal to 46.07 g/mol.
number of moles = (110.46 g/ 46.07 g/mol) = 2.4 mol

Then, multiply the number of moles by the Avogadro's number.
2.4 mol (6.022 x 10²³)
 number of molecules = 1.445 x 10²⁴

4 0

3 years ago

Which type of molecule is made from nucleotides?

murzikaleks [220]

Answer:

Nucleic acid is made from nucleotides

5 0

2 years ago

What is the sum of 0.0421 g + 5.263 g +2.13 g to the

myrzilka [38]

Answer: D

Explanation:

4 0

3 years ago

A compound distributes between benzene (solvent 1) and water (solvent 2) with a distribution coefficient, K = 2.7. If 1.0g of th

mote1985 [20]

Explanation:

The given data is as follows.

Solvent 1 = benzene, Solvent 2 = water

$K_{p}$ = 2.7, $V_{S_{2}}$ = 100 mL

$V_{S_{1}}$ = 10 mL, weight of compound = 1 g

Extract = 3

Therefore, calculate the fraction remaining as follows.

$f_{n} = [1 + K_{p}(\frac{V_{S_{2}}}{V_{S_{1}}})]^{-n}$

= $[1 + 2.7(\frac{100}{10})]^{-3}$

= $(28)^{-3}$

= $4.55 \times 10^{-5}$

Hence, weight of compound to be extracted = weight of compound - fraction remaining

= 1 - $4.55 \times 10^{-5}$

= 0.00001

or, = $1 \times 10^{-5}$

Thus, we can conclude that weight of compound that could be extracted is $1 \times 10^{-5}$ .

7 0

2 years ago

Read 2 more answers

A sample of oxygen occupies 20.1 liters under a pressure of 1520 torr at 25.0o What volume would it occupy at 25.0oC if the pres

Zolol [24]

Answer:

The volume that the sample of oxygen would occupy at 25 ° C if the pressure were reduced to 760.0 torr is 40.2 L

Explanation:

Boyle's law establishes the relationship between the pressure and the volume of a gas when the temperature is constant, so that the pressure of a gas in a closed container is inversely proportional to the volume of the container. That is, if the pressure increases, the volume decreases, while if the pressure decreases, the volume increases.

Boyle's law is expressed mathematically as:

Pressure * Volume = constant

or P * V = k

Considering an initial state 1 and a final state 2, it is true:

P1* V1= P2*V2

In this case:

P1= 20.1 L
V1= 1520 torr
P2= 760 torr
V2= ?

Replacing:

20.1 L* 1520 torr= 760 torr* V2

Solving:

$V2=\frac{20.1 L* 1520 torr}{760 torr}$

V2= 40.2 L

The volume that the sample of oxygen would occupy at 25 ° C if the pressure were reduced to 760.0 torr is 40.2 L

4 0

3 years ago