Biology Chapter 2 And 3 Quiz

All of the options listed can be used to represent a molecule. The name (molecular formula) provides information about the composition of the molecule, the electron-shell diagram shows the arrangement of electrons in the molecule's atoms, the structural formula depicts the connectivity between atoms, and the space filling model gives a three-dimensional representation of the molecule's atoms and their relative sizes. Therefore, all of these methods can be used to represent a molecule.

The given correct answer states that all of the definitions provided are true and none of them are incorrect. This means that each definition accurately describes the concepts it is referring to. Therefore, there is no incorrect definition among the options given.

The given correct answer is "A and B". This means that both the definitions of cation and anion are incorrect. The definition of cation states that it is a negatively charged ion, which is incorrect as cations are actually positively charged ions. Similarly, the definition of anion states that it is a positively charged ion, which is also incorrect as anions are actually negatively charged ions. Therefore, both A and B are incorrect definitions.

Ice is denser than water because the molecules in ice are arranged in a regular, hexagonal lattice structure, which creates open spaces or gaps between the molecules. These gaps result in a lower density compared to liquid water, where the molecules are more closely packed together. This is why ice floats on water.

Hydrogen bond: forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to an electropositive atom (eg. Oxygen, Nitrogen). This statement is correct because a hydrogen bond is a type of intermolecular bond that occurs when a hydrogen atom, which is covalently bonded to a highly electronegative atom such as oxygen or nitrogen, is attracted to an electronegative atom in a different molecule. This attraction is due to the partial positive charge on the hydrogen atom and the partial negative charge on the electronegative atom.

The given statement "pH = log [H+]" is incorrect. The correct statement is "pH = -log [H+]", where the negative sign indicates the inverse logarithm. The pH scale measures the acidity or alkalinity of a solution based on the concentration of hydrogen ions. The logarithm of the hydrogen ion concentration is taken to determine the pH value.

The explanation for the given correct answer is that the s orbital indeed has a sphere shape, while the p orbital has a figure-8 shape. This is a correct definition of the shapes of these orbitals in atomic structure. The s orbital is spherical in shape and can hold a maximum of 2 electrons, while the p orbital is dumbbell-shaped and can hold a maximum of 6 electrons.

The given statement "Molar mass = Molecular Mass" is incorrect because molar mass is the mass of one mole of a substance, while molecular mass is the mass of a single molecule of a substance. Molar mass is calculated by adding up the atomic masses of all the atoms in a molecule, while molecular mass is the sum of the atomic masses of all the atoms in a molecule. Therefore, molar mass and molecular mass are not the same.