Answer:
Parasites often show cospeciation because they must evolve with ther hosts.
Explanation:
0 100
15 50
30 25
45 12.5
Based on the observations, which of these is most likely David's inference?
A.The half life period of radioactive sodium is 15 hours.
B.The half life period of radioactive sodium is 50 hours.
C.The amount of sodium left in the container after 60 hours will be 10.5 grams.
D.The amount of sodium left in the container after 60 hours will be 1.5 grams.
Answer: A. The half life period of radioactive sodium is 15 hours.
Explanation:
Half life is the time taken by a reactant to reduce to its original concentration. It is designated by the symbol .
Given:
At 0 hours the amount of sodium in container is 100 grams
After 15 hours , the amount of sodium in container is 50 grams which is half of the original amount of 100 grams.
It will take 15 hours for half of a 100 g sample to decay to half of the amount i.e. 50 grams.
The correct option is d. attractive forces between different covalent molecules are the right response.
Intermolecular forces (IMFs) are attractive interactions between separate covalent molecules. These forces arise due to temporary imbalances in electron distribution, leading to regions of partial charge within molecules. Unlike covalent bonds that hold atoms within a molecule together, IMFs act between different molecules.
This includes forces like London dispersion forces (arising from temporary fluctuations in electron distribution), dipole-dipole interactions (between polar molecules with permanent dipoles), and hydrogen bonding (a special type of dipole-dipole interaction involving hydrogen bonded to electronegative atoms like oxygen, nitrogen, or fluorine). IMFs influence properties like boiling points, solubility, and phase changes. They're crucial in understanding the behavior of liquids and solids, particularly in cases involving non-metallic compounds.
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The correct answer is: d. attractive forces between separate covalent molecules
Intermolecular forces are the forces of attraction that exist between molecules, rather than within molecules (intramolecular forces). These forces play a crucial role in determining the physical properties of substances, such as boiling points, melting points, and solubility. The options a, b, c, and e are not correct descriptions of intermolecular forces:
a. Forces within covalent molecules that hold them together refer to intramolecular forces, such as covalent bonds, which involve the sharing of electrons between atoms within a molecule.
b. Electrostatic forces between ions are ionic bonds, which involve the transfer of electrons from one atom to another, leading to the formation of positively and negatively charged ions. This is not an example of intermolecular forces.
c. Bonds between hydrogen and oxygen atoms in water molecules refer to hydrogen bonds, which are a specific type of intermolecular force. However, this option does not encompass all types of intermolecular forces.
e. Covalent bonds within a network solid are intramolecular forces that hold the atoms together in a three-dimensional lattice, as seen in substances like diamond or quartz. This is not representative of intermolecular forces.
Therefore, the correct option is d, which correctly describes intermolecular forces as attractive forces between separate covalent molecules. These forces can include London dispersion forces (Van der Waals forces), dipole-dipole interactions, and hydrogen bonding, among others.
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b. boiling-point elevation
c. vapor-pressure lowering
d. freezing-point depression
Answer:
its D
Explanation:
i just got it correct on usatestprep
b. density
c. freezing point
d. solubility