Answer:
3 hydrogen bonds.
Explanation:
This is because the urea molecule has an oxygen atom bound with double bonds to the central carbon atom, and this oxygen can form a hydrogen bond with water, as well as both terminal amine groups that can also form a hydrogen bond each because of the lone pair of electrons on the nitrogen group.
Answer:
Fossils are the some traces or portions of the animals or plants, buried and preserved from past in rocks, sediments or ice.
Explanation:
Correct match is as follows-
- Mold and cast fossils- An organism is buried in sediment after it dies.The hard part of organism leave behind a empty space imprinted in the rock. Later sediments and minerals fill the space and harden to make the original copy of the organisms.
- Carbon film fossils- An organism buried in sediments gets squeezed and heated inside the earth , leaving behind a thin carbon outline of the organism on a rock.
- Amber fossil- An organism covered in tree resin or tree sap , which then hardens with the body of the organisms preserved inside.
- Ice fossil- An organism dies in a cold place on earth , its body becomes frozen and covered in layers of ice . The hard and soft part of the body may be preserved.
Answer:
A
Explanation:
B - Can't be - Ionic bonds are formed by oppositely charged ions
C - Can't be - This is a covalent bond
D - Can't be - This is an induced dipole or a van Der waals attraction
E - This is a permanent dipole dipole attraction
0.139 moles of plutonium are present in a sample containing 8.4 x 10²² atoms of Pt.
<h3>How to calculate number of moles?</h3>
The number of moles of a substance can be calculated using the following expression:
no of moles = no of molecules ÷ 6.02 × 10²³
According to this question, 8.4 × 10²² atoms of plutonium are present in the molecule of plutonium.
no of moles = 8.4 × 10²² = 6.02 × 10²³
no of moles = 1.39 × 10-¹
no of moles = 0.139moles
Therefore, 0.139 moles of plutonium are present in a sample containing 8.4 x 10²² atoms of Pt.
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