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Questions and Answers
Hydrophobic substances such as vegetable oil are:
Hydrophobic substances such as vegetable oil are:
Wax is a:
Wax is a:
Hydrophobic molecule
An atom is the smallest unit of an element that still retains properties of the element.
An atom is the smallest unit of an element that still retains properties of the element.
true
All atoms of a particular element have different numbers of protons in their nuclei.
All atoms of a particular element have different numbers of protons in their nuclei.
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Atoms of various molecules differ in their number of:
Atoms of various molecules differ in their number of:
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Neutrons and protons are equal in mass.
Neutrons and protons are equal in mass.
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Neutrons and protons have a mass of approximately:
Neutrons and protons have a mass of approximately:
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Buffers are substances that help resist shifts in pH by _____ and _____
Buffers are substances that help resist shifts in pH by _____ and _____
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The mass number of an element can be easily approximated by adding together the number of:
The mass number of an element can be easily approximated by adding together the number of:
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In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by:
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by:
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The slight negative charge at one end of a water molecule is attracted to the slight positive charge of another molecule. This attraction is called a:
The slight negative charge at one end of a water molecule is attracted to the slight positive charge of another molecule. This attraction is called a:
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A solution containing $10^{-7}$ moles of hydroxyl ions [OH-] per liter is:
A solution containing $10^{-7}$ moles of hydroxyl ions [OH-] per liter is:
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What is the approximate mass of an atom with 16 neutrons, 15 protons, and 15 electrons?
What is the approximate mass of an atom with 16 neutrons, 15 protons, and 15 electrons?
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A covalent bond is likely to be polar when:
A covalent bond is likely to be polar when:
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Many mammals control their body temperature by sweating, caused by which of water's properties?
Many mammals control their body temperature by sweating, caused by which of water's properties?
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Atoms whose outer electron shells contain 8 electrons are:
Atoms whose outer electron shells contain 8 electrons are:
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A system that maintains a relatively constant pH when either acids or bases are added is called a:
A system that maintains a relatively constant pH when either acids or bases are added is called a:
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The atomic number indicates the number of:
The atomic number indicates the number of:
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Blood that comes in contact with respiring cells will:
Blood that comes in contact with respiring cells will:
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Why does ice float in water?
Why does ice float in water?
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If pure, freshly distilled water has [OH-] = [H+], then the pH is:
If pure, freshly distilled water has [OH-] = [H+], then the pH is:
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Weak interactions include:
Weak interactions include:
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What four elements make up 96% of living matter?
What four elements make up 96% of living matter?
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Water striders are an example of:
Water striders are an example of:
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4 degrees is water's:
4 degrees is water's:
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A covalent chemical bond is formed when:
A covalent chemical bond is formed when:
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If you mix two beakers together with different pHs, the new pH will be the:
If you mix two beakers together with different pHs, the new pH will be the:
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What gives rise to the cohesiveness of water molecules?
What gives rise to the cohesiveness of water molecules?
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Study Notes
Key Concepts in Biology
- Hydrophobic substances, like vegetable oil, are nonpolar and repel water.
- Waxes are classified as hydrophobic molecules, contributing to waterproofing in various organisms.
- An atom is the smallest unit of an element, retaining the element's properties.
- Atoms of a particular element have identical numbers of protons in their nuclei, defining the element.
- Different atoms comprise various molecules, differentiated by varying numbers of subatomic particles.
- Neutrons and protons have equal mass, approximately 1 Dalton (also known as atomic mass unit or amu).
- Buffers stabilize pH levels by donating H+ when depleted and accepting H+ when in excess.
- The mass number of an element approximates the sum of its protons and neutrons.
Water and Its Properties
- Water molecules consist of two hydrogen atoms bonded to one oxygen atom via polar covalent bonds.
- The slight charges of water molecules lead to hydrogen bonds, a key reason for interactions between water molecules.
- A solution with 10^-7 moles of hydroxyl ions (OH-) per liter is neutral, indicating equal concentrations of H+ and OH-.
- For an atom with 16 neutrons, 15 protons, and 15 electrons, the approximate mass is 51 Daltons.
- Polar covalent bonds are likely when one of the atoms is significantly more electronegative.
- Many mammals regulate body temperature through sweating, a process involving the heat absorption when hydrogen bonds break.
- Atoms with eight electrons in their outer shell are considered stable, chemically inactive, or inert.
Chemical Interactions and Solutions
- A buffer system maintains consistent pH despite the addition of acids or bases.
- Atomic number indicates the number of protons in an atom's nucleus, which determines the element's identity.
- Blood interacting with respiring cells typically experiences a slight decrease in pH due to metabolic processes.
- Ice floats on water because hydrogen bonds create a stable structure that keeps ice molecules farther apart than those in liquid water.
- Pure, freshly distilled water has equal concentrations of H+ and OH-, resulting in a neutral pH of 7.
- Weak interactions such as ionic bonds, van der Waals interactions, and hydrogen bonds play crucial roles in molecular structure and function.
Elements and Nature
- Four elements—carbon, hydrogen, nitrogen, and oxygen—make up approximately 96% of living matter.
- The high surface tension of water is illustrated by the behavior of water striders, allowing them to walk on water.
- Water's densest point occurs at 4 degrees Celsius, an unusual property that influences aquatic ecosystems.
- Covalent bonds involve the sharing of outer-shell electrons, essential for forming stable molecules.
- Mixing two solutions with different pHs leads to a new pH that is the average of the two.
- Cohesiveness in water molecules arises from hydrogen bonding, enabling phenomena such as surface tension and capillarity.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of key concepts from AP Biology Chapters 2 and 3 with this set of flashcards. Explore essential terms like hydrophobic substances, atoms, and their properties. Perfect for quick review or study sessions!
