{
  "name": "Chemistry Essentials (101)",
  "front_language": "Chemistry",
  "back_language": "English",
  "cards": [
    { "front": "Matter", "back": "Anything that has mass and takes up space (volume).", "level": "101", "tags": ["matter"], "example_front": "Air, water, and rock are all examples of matter.", "example_back": "Even gases count as matter because they have mass and occupy volume." },
    { "front": "Mass", "back": "A measure of the amount of matter in an object, usually given in grams or kilograms.", "level": "101", "tags": ["matter"], "example_front": "The mass of the sample was measured as 12.4 grams.", "example_back": "Mass stays the same no matter where the object is, unlike weight." },
    { "front": "Volume", "back": "The amount of three-dimensional space a substance or object occupies.", "level": "101", "tags": ["matter"], "example_front": "The liquid filled a volume of 250 milliliters.", "example_back": "Volume is often measured with a graduated cylinder in the lab." },
    { "front": "Density", "back": "The mass of a substance divided by its volume, often expressed in g/mL or g/cm³.", "level": "101", "tags": ["matter"], "example_front": "Gold has a density of about 19.3 g/cm³.", "example_back": "A high density means a lot of mass is packed into a small volume." },
    { "front": "Mixture", "back": "A combination of two or more substances that are physically combined but not chemically bonded.", "level": "101", "tags": ["matter"], "example_front": "Salt water is a mixture of salt and water.", "example_back": "The salt can be separated from the water by evaporation." },
    { "front": "Element", "back": "A pure substance made of only one type of atom, which cannot be broken down into simpler substances by chemical means.", "level": "101", "tags": ["periodic-table"], "example_front": "Oxygen and gold are both examples of elements.", "example_back": "Each element has its own unique symbol on the periodic table." },
    { "front": "Compound", "back": "A substance formed when two or more elements chemically combine in a fixed ratio.", "level": "101", "tags": ["periodic-table"], "example_front": "Water (H₂O) is a compound made of hydrogen and oxygen.", "example_back": "Unlike a mixture, a compound's components can't be separated by simple physical methods." },
    { "front": "Molecule", "back": "Two or more atoms held together by chemical bonds; the smallest unit of a compound that retains its properties.", "level": "101", "tags": ["periodic-table"], "example_front": "A water molecule consists of two hydrogen atoms and one oxygen atom.", "example_back": "Molecules can be made of the same element (O₂) or different elements (H₂O)." },
    { "front": "Atom", "back": "The smallest particle of an element that retains the chemical properties of that element.", "level": "101", "tags": ["atomic-structure"], "example_front": "A single atom of carbon contains six protons.", "example_back": "The number of protons in an atom determines which element it is." },
    { "front": "Proton", "back": "A positively charged particle found in the nucleus of an atom.", "level": "101", "tags": ["atomic-structure"], "example_front": "An atom with six protons is always carbon.", "example_back": "The number of protons gives an element its atomic number." },
    { "front": "Neutron", "back": "A neutral (uncharged) particle found in the nucleus of an atom, alongside protons.", "level": "101", "tags": ["atomic-structure"], "example_front": "Carbon-14 has two more neutrons than carbon-12.", "example_back": "Neutrons add mass to the nucleus without changing the element's charge." },
    { "front": "Electron", "back": "A negatively charged particle that orbits the nucleus of an atom in energy levels or shells.", "level": "101", "tags": ["atomic-structure"], "example_front": "Electrons are responsible for forming chemical bonds between atoms.", "example_back": "An atom is electrically neutral when it has equal numbers of protons and electrons." },
    { "front": "Atomic number", "back": "The number of protons in the nucleus of an atom, which determines the element's identity.", "level": "101", "tags": ["atomic-structure"], "example_front": "Hydrogen has an atomic number of 1.", "example_back": "Elements on the periodic table are arranged in order of increasing atomic number." },
    { "front": "Isotope", "back": "An atom of the same element with a different number of neutrons, giving it a different mass.", "level": "101", "tags": ["atomic-structure"], "example_front": "Carbon-12 and carbon-14 are isotopes of carbon.", "example_back": "Isotopes have the same atomic number but different mass numbers." },
    { "front": "Periodic table", "back": "A chart that organizes all known elements by increasing atomic number and by similar chemical properties.", "level": "101", "tags": ["periodic-table"], "example_front": "Elements in the same column of the periodic table often react in similar ways.", "example_back": "The periodic table groups elements into rows (periods) and columns (groups)." },
    { "front": "Valence electron", "back": "An electron in the outermost shell of an atom that can participate in forming chemical bonds.", "level": "101", "tags": ["bonding"], "example_front": "Carbon has four valence electrons, which is why it can form four bonds.", "example_back": "Atoms tend to gain, lose, or share valence electrons to become more stable." },
    { "front": "Ionic bond", "back": "A chemical bond formed when one atom transfers an electron to another, creating oppositely charged ions that attract each other.", "level": "101", "tags": ["bonding"], "example_front": "Table salt (NaCl) is held together by an ionic bond between sodium and chlorine.", "example_back": "Sodium loses an electron to become Na⁺, and chlorine gains it to become Cl⁻." },
    { "front": "Covalent bond", "back": "A chemical bond formed when two atoms share one or more pairs of electrons.", "level": "101", "tags": ["bonding"], "example_front": "The two oxygen atoms in O₂ are joined by a covalent bond.", "example_back": "Covalent bonds typically form between nonmetal atoms." },
    { "front": "Polar molecule", "back": "A molecule with an uneven distribution of electrical charge, giving it a slightly positive end and a slightly negative end.", "level": "101", "tags": ["bonding"], "example_front": "Water is a polar molecule because oxygen pulls electrons more strongly than hydrogen does.", "example_back": "This polarity is why water can dissolve so many other substances." },
    { "front": "Chemical reaction", "back": "A process in which one or more substances are transformed into different substances with new properties.", "level": "101", "tags": ["reactions"], "example_front": "Burning wood is a chemical reaction that produces ash, smoke, and gases.", "example_back": "Signs of a chemical reaction include a color change, gas production, or a temperature change." },
    { "front": "Reactant", "back": "A starting substance that takes part in and is changed by a chemical reaction.", "level": "101", "tags": ["reactions"], "example_front": "In the reaction 2H₂ + O₂ → 2H₂O, hydrogen and oxygen are the reactants.", "example_back": "Reactants are written on the left side of a chemical equation." },
    { "front": "Product", "back": "A substance that is formed as a result of a chemical reaction.", "level": "101", "tags": ["reactions"], "example_front": "In the same reaction, water is the product.", "example_back": "Products are written on the right side of a chemical equation." },
    { "front": "Chemical equation", "back": "A symbolic representation of a chemical reaction, showing reactants and products with their formulas.", "level": "101", "tags": ["reactions"], "example_front": "The chemical equation 2H₂ + O₂ → 2H₂O describes hydrogen burning in oxygen.", "example_back": "An arrow separates the reactants from the products." },
    { "front": "Balanced equation", "back": "A chemical equation in which the number of atoms of each element is equal on both sides, following the law of conservation of mass.", "level": "101", "tags": ["reactions"], "example_front": "2H₂ + O₂ → 2H₂O is a balanced equation because there are four hydrogen and two oxygen atoms on each side.", "example_back": "Balancing equations ensures no atoms are created or destroyed during the reaction." },
    { "front": "Catalyst", "back": "A substance that speeds up a chemical reaction without being consumed or permanently changed itself.", "level": "101", "tags": ["reactions"], "example_front": "Enzymes act as catalysts that speed up reactions in living cells.", "example_back": "A catalyst lowers the energy needed to start a reaction but doesn't appear in the final products." },
    { "front": "Mole", "back": "The SI unit for the amount of a substance, equal to 6.022 × 10²³ particles (Avogadro's number).", "level": "101", "tags": ["stoichiometry"], "example_front": "One mole of carbon atoms has a mass of about 12 grams.", "example_back": "The mole lets chemists count atoms and molecules by weighing them." },
    { "front": "Avogadro's number", "back": "The number of particles (atoms, molecules, or ions) in one mole of a substance, approximately 6.022 × 10²³.", "level": "101", "tags": ["stoichiometry"], "example_front": "Avogadro's number tells us how many molecules are in one mole of water.", "example_back": "This huge number bridges the gap between the microscopic and the measurable scale." },
    { "front": "Molar mass", "back": "The mass of one mole of a substance, expressed in grams per mole (g/mol).", "level": "101", "tags": ["stoichiometry"], "example_front": "The molar mass of water is about 18 g/mol.", "example_back": "Molar mass is found by adding up the atomic masses of all atoms in the formula." },
    { "front": "Acid", "back": "A substance that releases hydrogen ions (H⁺) in water and has a pH less than 7.", "level": "101", "tags": ["acids-bases"], "example_front": "Lemon juice is acidic because it contains citric acid.", "example_back": "Acids often taste sour and can react with metals to produce hydrogen gas." },
    { "front": "Base", "back": "A substance that accepts hydrogen ions or releases hydroxide ions (OH⁻) in water, with a pH greater than 7.", "level": "101", "tags": ["acids-bases"], "example_front": "Baking soda dissolved in water acts as a mild base.", "example_back": "Bases often feel slippery and can neutralize acids." },
    { "front": "pH", "back": "A scale from 0 to 14 that measures how acidic or basic a solution is, with 7 being neutral.", "level": "101", "tags": ["acids-bases"], "example_front": "Pure water has a pH of 7, making it neutral.", "example_back": "A lower pH means a more acidic solution, and a higher pH means a more basic one." },
    { "front": "Solution", "back": "A homogeneous mixture in which one substance (the solute) is dissolved completely in another (the solvent).", "level": "101", "tags": ["solutions"], "example_front": "When sugar dissolves completely in water, it forms a solution.", "example_back": "Unlike some mixtures, a solution looks uniform throughout and won't settle out over time." }
  ]
}