Polarity & Water
What does it mean if a molecule is polar?
It has unequal sharing of electrons, creating partial charges
How many electrons can fit in the first energy level?
2 electrons
What are the four main types of macromolecules?
Carbohydrates, lipids, proteins, and nucleic acids
What tool is most accurate for measuring liquid volume?
A graduated cylinder
What kind of bond shares electrons?
Covalent bond
Why is water considered a polar molecule?
Oxygen pulls electrons more strongly than hydrogen
What is the electron configuration of oxygen?
1s² 2s² 2p⁴
Which macromolecule includes enzymes?
Proteins
What’s the first step in using a graduated cylinder?
Place it on a flat surface and read at eye level
What is an ionic bond?
A bond where electrons are transferred from one atom to another
What is hydrogen bonding?
A weak attraction between a hydrogen atom and an electronegative atom like oxygen or nitrogen
What do valence electrons determine?
Chemical reactivity and bonding
What type of reaction builds macromolecules?
Dehydration synthesis
Why wear goggles in the lab?
To protect your eyes from harmful chemicals
What kind of bond holds water molecules together?
Hydrogen bonds
What causes water to have a high surface tension?
Hydrogen bonds between water molecules
Why do atoms form bonds based on electron configuration?
To achieve a full outer shell (stable octet)
What are the monomers of proteins?
Amino acids
What should you do if a chemical spills?
Tell your instructor and follow proper cleanup procedures
Which bond forms between hydrogen and electronegative atoms?
Hydrogen bond
Explain how polarity helps soap remove grease.
Soap’s polar end bonds with water; nonpolar end bonds with grease, breaking it apart
Draw and explain calcium chloride’s (CaCl₂) configuration
Ca loses 2 electrons (2+), each Cl gains 1 (1−), forming ionic bonds
Which macromolecule stores genetic information?
Nucleic acids (DNA and RNA)
Describe the purpose of a titration.
To determine the concentration of an unknown solution by reacting it with a known one
Why is NaCl an example of an ionic bond?
Sodium donates an electron to chlorine, forming ions that attract each other