general chemistry

• What is a compound?

  A compound is a substance that contains two or more different types of atoms chemically bonded together
• What is the chemical formula for water?

  The chemical formula for water is H₂O
• How do we represent a chemical reaction?

  A chemical reaction can be represented with a word equation and a chemical equation using symbols
• Why must chemical equations be balanced?

  Because atoms are not created or destroyed in a chemical reaction, the same number of each type of atom must be on both sides
• What is the first step in balancing a chemical equation?

  Start balancing atoms that are only in compounds
• How do you balance hydrogen and oxygen in a reaction involving water?

  By adjusting the coefficients in front of H₂O and O₂ to ensure the number of each atom is equal on both sides
• What is a mixture?

  A mixture is any combination of different types of elements and compounds that aren't chemically bonded together
• How can you separate large insoluble particles from a liquid?

  By using filtration
• What is crystallization used for?

  To separate a solute from a solvent after evaporating the solvent
• What is the process of distillation?

  Heating a solution to create gas, which is then cooled to condense back into a liquid
• What is fractional distillation?

  It involves separating different liquids in a mixture based on their boiling points
• What are the three main states of matter?

  Solid, liquid, and gas
• How do particles behave in a solid state?

  Particles vibrate around fixed positions
• What happens to particles when a substance melts or evaporates?

  Energy is supplied to overcome the electrostatic forces of attraction between the particles
• What do state symbols indicate in chemical equations?

  They indicate the state of substances: (s) for solid, (l) for liquid, (g) for gas, and (aq) for aqueous
• Who proposed the plum pudding model of the atom?

  JJ Thompson
• What did Ernest Rutherford discover about the atom?

  He discovered that the positive charge is concentrated in a small nucleus
• What did Niels Bohr contribute to atomic theory?

  He discovered that electrons exist in shells or orbitals around the nucleus
• What are protons and neutrons collectively known as?

  They are collectively known as nucleons
• What is the charge of a proton?

  +1
• What is the charge of a neutron?

  0
• What is the charge of an electron?

  • 1
• What does the atomic number represent?

  The atomic number represents the number of protons in the nucleus
• What does the mass number represent?

  The mass number represents the total number of protons and neutrons in the nucleus
• What are isotopes?

  Isotopes are atoms of the same element with different numbers of neutrons
• What is relative atomic mass (RAM)?

  Relative atomic mass is the weighted average mass of an element's isotopes compared to carbon-12
• How is the average relative atomic mass calculated?

  By adding the total masses of all isotopes and dividing by the total number of atoms
• What did Dmitri Mendeleev contribute to the periodic table?

  Dmitri Mendeleev grouped elements based on their properties and predicted undiscovered elements
• How do electrons fill the shells around the nucleus?

  Electrons fill the shells from the inside out, with a maximum of 2 in the first shell and 8 in the second and third shells
• What are the groups in the periodic table?

  Groups are columns in the periodic table that indicate the number of electrons in the outer shell
• What are alkali metals?

  Alkali metals are in group one and have one electron in their outer shell
• How does reactivity change in alkali metals as you move down the group?

  Reactivity increases as you move down the group due to weaker electrostatic attraction
• What are halogens?

  Halogens are in group seven and have seven electrons in their outer shell
• How does reactivity change in halogens as you move down the group?

  Reactivity decreases as you move down the group
• What are noble gases?

  Noble gases are in group zero and have a full outer shell, making them very unreactive
• What happens to metals when they lose electrons?

  They become positively charged ions
• What charge do group one metals form when they become ions?

  Group one metals form +1 ions
• What charge do group two metals form when they become ions?

  Group two metals form +2 ions
• What charge do group seven nonmetals form when they become ions?

  Group seven nonmetals form -1 ions
• What charge do group six nonmetals form when they become ions?

  Group six nonmetals form -2 ions