Chemistry Flashcards
Describe the three subatomic particles.
Protons: Positively charged, found in the nucleus.
Neutrons: No charge, found in the nucleus.
Electrons: Negatively charged, orbit the nucleus.
Distinguish between the atomic number and the mass number of an element.
Atomic Number: Number of protons in an atom.
Mass Number: Sum of protons and neutrons in the nucleus.
Distinguish between ionic bonds, polar covalent bonds, and non-polar covalent bonds and provide examples of each.
Ionic Bond: Electron transfer (e.g., NaCl).
Polar Covalent Bond: Unequal electron sharing (e.g., H₂O).
Non-Polar Covalent Bond: Equal electron sharing (e.g., O₂).
Given the electronegativity of two atoms, predict the type of bond they will form.
Large difference (>1.7) → Ionic bond.
Moderate difference (0.5–1.7) → Polar covalent bond.
Small difference (<0.5) → Non-polar covalent bond.
Describe the difference between CO₂ and H₂O that accounts for their different physical and chemical properties.
CO₂: Linear, non-polar, gas at room temp.
H₂O: Bent shape, polar, liquid at room temp due to hydrogen bonding.
Draw a water molecule surrounded by 4 other water molecules and distinguish between hydrogen bonds and covalent bonds.
Covalent Bonds: Hold H and O within a single water molecule.
Hydrogen Bonds: Weak attractions between adjacent water molecules.
Describe the properties of water that contribute to Earth’s suitability for life.
High heat capacity
Solvent properties
Cohesion & adhesion
Ice floats (lower density when frozen)
Cohesion
Water molecules stick together (surface tension).
Adhesion
Water sticks to other surfaces (capillary action).
Hydration
Water surrounds solutes
Solute
Dissolved substance
Solvent
Dissolving agent (liquid)
Molarity
Concentration of a solution
Specific heat
Energy to change temp
Heat of vaporization
Energy to turn liquid to gas
Evaporative cooling
Heat loss via evaporation
Hydrophilic
Water-attracting
Hydrophobic
Water-repelling
Explain why it takes longer to heat a cup of water than a cup of oil.
Water has a higher specific heat capacity, requiring more energy to raise its temperature compared to oil.
Describe what happens when a crystal of sucrose dissolves in water.
Water molecules surround sucrose molecules, forming hydrogen bonds and separating them into solution.
Describe the relationship between the density of water and temperature and explain how this has impacted the evolution of life on Earth.
Water is less dense as a solid (ice floats).
This prevents lakes/oceans from freezing solid, allowing aquatic life to survive.
Provide examples of the role of weak bonds in biological molecules.
Hydrogen bonds: Hold DNA strands together.
Ionic interactions: Stabilize protein structure.
Describe the exclusion of hydrophobic molecules by water molecules.
Water forms hydrogen bonds with itself, pushing non-polar molecules together (e.g., oil droplets in water).
What are isotopes, and how are they useful in research and medicine?
Isotopes are atoms of the same element with different numbers of neutrons, meaning they have different mass numbers but the same chemical properties.
Usefulness: Isotopes help in medical imaging, cancer treatment, and understanding biological and geological processes.
