1.
In which of these are the electrons always shared unequally?
Correct Answer
B. Polar covalent bond
Explanation
In a polar covalent bond, the electrons are always shared unequally between the two atoms. This is because one atom has a higher electronegativity than the other, causing it to attract the shared electrons more strongly. As a result, the electron density is shifted towards the more electronegative atom, creating partial positive and negative charges within the molecule. This unequal sharing of electrons in a polar covalent bond leads to the formation of a dipole, which can result in unique chemical properties and interactions.
2.
An example of a hydrogen bond would be the
Correct Answer
D. Bond between two water molecules.
Explanation
A hydrogen bond is a type of intermolecular bond that occurs when a hydrogen atom is bonded to a highly electronegative atom (such as oxygen or nitrogen) and is attracted to another electronegative atom nearby. In the case of two water molecules, the oxygen atom in one molecule is attracted to the hydrogen atom in the other molecule, forming a hydrogen bond. This bond is important in the unique properties of water, such as its high boiling point and surface tension.
3.
Water flows freely, but does not separate into individual molecules because water is
Correct Answer
A. Cohesive.
Explanation
Water flows freely because it is cohesive. Cohesion refers to the attraction between molecules of the same substance, and in the case of water, it is due to the hydrogen bonding between water molecules. This cohesive force allows water molecules to stick together, forming a continuous flow. It prevents the water from separating into individual molecules and allows it to maintain its liquid state.
4.
Water can absorb a large amount of heat without much change in temperature, and therefore it has
Correct Answer
A. A high heat capacity.
Explanation
Water has a high heat capacity because it can absorb a large amount of heat without a significant change in temperature. This is due to the strong hydrogen bonding between water molecules. When heat is added to water, the hydrogen bonds absorb the energy and prevent the temperature from rising rapidly. This property of water is important for regulating temperature in living organisms and for moderating climate on Earth.
5.
Which of these properties of water cannot be attributed to hydrogen bonding between water molecules?
Correct Answer
C. Water is a solvent for many molecules.
Explanation
The property of water being a solvent for many molecules is not directly attributed to hydrogen bonding between water molecules. It is primarily due to the polar nature of water molecules, which allows them to interact with and dissolve other polar or charged molecules. Hydrogen bonding, on the other hand, is responsible for properties such as water's high boiling point, surface tension, and cohesion.
6.
This Graph illustrates
Correct Answer
D. That ice is less dense than water.As well as Why Ice is more dense than water. are correct
Explanation
The graph in question likely shows the relationship between the density of ice and water. It is known that ice is less dense than water, which is why it floats on water. However, it is also true that ice can be more dense than water under certain conditions. This can occur when the ice is subjected to high pressure, causing the water molecules to pack more closely together. Therefore, both statements are correct.
7.
Acids
Correct Answer
A. Release hydrogen ions in solution.
Explanation
Acids release hydrogen ions in solution. This is because acids are substances that can donate protons (H+) to a solution. When an acid dissolves in water, it releases these hydrogen ions, which are responsible for the acidic properties of the solution. The release of hydrogen ions lowers the pH of the solution, making it more acidic. Therefore, the correct answer is that acids release hydrogen ions in solution.
8.
Which of these best describes the changes that occur when a solution goes from pH 5 to pH 8?
Correct Answer
A. The hydrogen ion concentration decreases as the solution goes from acidic to basic
Explanation
pH is a measure of the concentration of hydrogen ions in a solution. A pH of 5 indicates an acidic solution with a higher concentration of hydrogen ions, while a pH of 8 indicates a basic solution with a lower concentration of hydrogen ions. Therefore, as the solution goes from pH 5 to pH 8, the hydrogen ion concentration decreases.
9.
When water dissociates, it releases
Correct Answer
A. Equal amounts of H+ and OH–.
Explanation
When water dissociates, it releases equal amounts of H+ and OH– ions. This is because water molecules can ionize into H+ ions (protons) and OH– ions (hydroxide ions). The concentration of H+ ions is equal to the concentration of OH– ions, resulting in a neutral solution. This is known as the self-ionization of water.
10.
Rainwater has a pH of about 5.6; therefore, rainwater is
Correct Answer
B. An acidic solution.
Explanation
Rainwater has a pH of about 5.6, which is below 7 on the pH scale. A pH below 7 indicates acidity, so rainwater is considered an acidic solution.
11.
If a chemical accepted H+ from the surrounding solution, the chemical could be
Correct Answer
C. An acid.
Explanation
If a chemical accepts H+ ions from the surrounding solution, it means that it is capable of donating or releasing H+ ions. This behavior is characteristic of acids, as they are substances that can donate protons or H+ ions. Therefore, the correct answer is "an acid".