Answer:
D. Hydrogen bonds between complementary base pairs89
Explanation:
A DNA molecule is composed of two long polynucleotide chains made of four types of nucleotide subunits, two purines (adenine and guanine) and two pyrimidines (cytosine and thymine). These nucleotides are joined by covalent bonds forming a phosphate-sugar backbone. <em>These strands are held to one another with hydrogen bonds between the base portions of complementary nucleotides.</em>
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The full question asks to decide whether the gas was a specific gas. That part is missing in your question. You need to decide whether the gas in the flask is pure helium.
To decide it you can find the molar mass of the gas in the flask, using the ideal gas equation pV = nRT, and then compare with the molar mass of the He.
From pV = nRT you can find n, after that using the mass of gass in the flask you use MM = mass/moles.
1) From pV = nRT, n = pV / RT
Data:
V = 118 ml = 0.118 liter
R = 0.082 atm*liter/mol*K
p = 768 torr * 1 atm / 760 torr = 1.0105 atm
T = 35 + 273.15 = 308.15 K
n = 1.015 atm * 0.118 liter / [ 0.082 atm*liter/K*mol * 308.15K] =0.00472 mol
mass of gas = mass of the fask with the gas - mass of the flasl evacuated = 97.171 g - 97.129 g = 0.042
=> MM = mass/n = 0.042 / 0.00472 = 8.90 g/mol
Now from a periodic table or a table you get that the molar mass of He is 4g/mol
So the numbers say that this gas is not pure helium , because its molar mass is more than double of the molar mass of helium gas.
Answer:
They are multilayered
Spacesuits provide protection from radiation and offer normal air pressure inside
Explanation:
The hydrogen bonding in H₂O is stronger than that of HF
Explanation:
Hydrogen bonds are special dipole-dipole attraction in which electrostatic attraction is established between hydrogen atom of one molecule and the electronegative atom of a neighboring molecule.
- The strength of hydrogen bonds depends on the how electronegative an atom is.
- Electronegativity refers to the tendency of an atom to gain electrons.
- The higher the value, the higher the tendency.
- This why oxygen with a higher electronegativity will form a stronger hydrogen bond with hydrogen compared to fluorine.
Learn more:
hydrogen bond brainly.com/question/12408823
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