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Orlov [11]
4 years ago
15

1. The creatures preserved in the Burgess Shale fossils are most closely related to modern

Chemistry
1 answer:
fomenos4 years ago
3 0
Answer: D. Insects

Fossils that are preserved in the Burgess Shale are mostly the remains of soft-bodied organisms.

So the answer is D because insects don’t really have bones like the rest of the other options. They have exoskeletons which protects their organs and gives them support for moving around.
You might be interested in
Given the following list of densities, which materials would float in a molten vat of lead provided that they do not themselves
vampirchik [111]

Answer:

b. glass and charcoal

Explanation:

Step 1: Given data

  • Density of Pb: 11.4 g/mL
  • Density of Glass: 2.6 g/mL
  • Density of Au: 19.3 g/mL
  • Density of charcoal: 0.57 g/mL
  • Density of platinum: 21.4 g/mL

Step 2: Determine which material will float in molten lead

Density is an intrinsic property of matter. Less dense materials float in more dense materials. The materials whose density is lower than that of lead and will therefore float on it are glass and charcoal.

8 0
3 years ago
2. Which of the changes indicated are oxidations
sergeinik [125]

Answer:

A) Oxidized

B) Reduced

C) Oxidized

D) Oxidized

Explanation:

A) Cu becomes Cu²⁺

oxidation state increased from 0 to +2. It gets oxidize.

B) Sn⁺⁴ becomes Sn²⁺

oxidation state decreased from +4 to +2. It gets reduced.

C) Cr³⁺ becomes Cr⁺⁶

oxidation state increased from +3 to +6. It gets oxidize.

D) Ag becomes Ag⁺

oxidation state increased from 0 to +1. It gets oxidize.

Oxidation:

Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.

Reduction:

Reduction involve the gain of electron and oxidation number is decreased.

<em>Consider the following reactions. </em>

4KI + 2CuCl₂  →   2CuI  + I₂  + 4KCl

the oxidation state of copper is changed from +2 to +1 so copper get reduced.

CO + H₂O   →  CO₂ + H₂

the oxidation state of carbon is +2 on reactant  side and on product side it becomes  +4 so carbon get oxidized.

5 0
4 years ago
What isa the UIPAC name H3C<br> CH2-CH2-CH3<br> CH-CH-CH2-CH3<br> H3C—CH<br> CH<br> CH3
aliina [53]

Answer:

4–ethyl–2,3–dimethylheptane

Explanation:

To name the compound given above, do the following:

1. Locate the longest continuous carbon chain. This gives the parent name of the compound. In this case, the longest continuous carbon chain is 7. Thus the parent name is Heptane.

2. Identify the substituent group attached to the compound. In this case, the substituent group attached are:

a. Methyl (–CH₃). There are two methyl group attached.

b. Ethyl (–CH₂CH₃)

3. Locate the position of the substituent group attached to the compound by naming alphabetically.

a. The two Methyl (–CH₃) groups are located at carbon 2 and 3

b. The Ethyl (–CH₂CH₃) is located at carbon 4.

NOTE: The position of the Ethyl (–CH₂CH₃) group is the same from both side so we consider the lowest count for the methyl group.

4. Combine the above to obtain the name of the compound.

The name of the compound is:

4–ethyl–2,3–dimethylheptane

3 0
3 years ago
Why does Hg2+ have a negative standard entropy
lidiya [134]

Answer:

Hg∧2+ has a negative standard entropy because the ions are highly solvated in aqueous phase; smaller the ionic size, the more highly it is surrounded by solvated ions. Therefore it will be in highly ordered state hence the entropy decreases.

Hg2 ^2+ has a positive standard entropy because the ionic size of Hg^2+ is smaller than Hg2 ^2+, so therefore the Hg^2+ is highly solvated and that means that it is in highly ordered state.  Hg2 ^2+  is not highly solvated so it will have a positive entropy

Explanation:

The values of standard entropy of aqueous ions has a negative standard entropy because the ions are highly solvated in aqueous phase; smaller the ionic size, the more highly it is surrounded by solvated ions. Therefore it will be in highly ordered state hence the entropy decreases.

Hg2 ^2+ has a positive standard entropy because the ionic size of Hg^2+ is smaller than Hg2 ^2+, so therefore the Hg^2+ is highly solvated and that means that it is in highly ordered state.  Hg2 ^2+  is not highly solvated so it will have a positive entropy

4 0
3 years ago
How many liters of Cl2 gas will you have if you are using 63 g of Na?
ELEN [110]

Answer:

You will have 19.9L of Cl2

Explanation:

We can solve this question using:

PV = nRT; V = nRT/P

<em>Where V is the volume of the gas</em>

<em>n the moles of Cl2</em>

<em>R is gas constant = 0.082atmL/molK</em>

<em>T is 273.15K assuming STP conditions</em>

<em>P is 1atm at STP</em>

The moles of 63g of Cl2 gas are -molar mass: 70.906g/mol:

63g * (1mol / 70.906g) = 0.8885 moles

Replacing:

V = 0.8885mol*0.082atmL/molK*273.15K/1atm

V = You will have 19.9L of Cl2

6 0
3 years ago
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