Chemical Combination Flashcards
What is stoichiometry, and why is it important in chemistry?
Stoichiometry is the study of the quantitative relationships between the amounts of reactants and products in a chemical reaction. It allows chemists to predict the quantities of substances consumed and produced in a reaction, ensuring reactions are carried out efficiently.
What is the Law of Definite Proportions?
The Law of Definite Proportions states that a chemical compound always contains the same elements in the same proportion by mass, regardless of the sample size or source.
What is the Law of Multiple Proportions, and can you provide an example?
The Law of Multiple Proportions states that when two elements combine to form more than one compound, the ratios of the masses of the second element that combine with a fixed mass of the first element will be small whole numbers. Example: Carbon forms CO and CO₂ with oxygen. For every 12g of carbon, CO has 16g of oxygen, while CO₂ has 32g of oxygen. The ratio of oxygen masses (32:16) is 2:1.
How does the Law of Conservation of Matter apply to chemical reactions?
The Law of Conservation of Matter states that matter is neither created nor destroyed in a chemical reaction. The mass of the reactants equals the mass of the products. This principle is reflected in balanced chemical equations.
What does Gay-Lussac’s Law of Combining Volumes state?
Gay-Lussac’s Law states that the volumes of gases reacting together at the same temperature and pressure are in simple whole number ratios. For example, 2 volumes of hydrogen gas combine with 1 volume of oxygen gas to form 2 volumes of water vapor (2H₂ + O₂ → 2H₂O).
What is Avogadro’s Law and how does it relate to gases?
Avogadro’s Law states that equal volumes of all gases, at the same temperature and pressure, contain the same number of molecules. This law helps to understand the relationship between the volume of gas and the number of molecules it contains.
What are chemical symbols and chemical formulae used for?
Chemical symbols represent elements (e.g., H for hydrogen, O for oxygen), while chemical formulae represent compounds, showing the types and numbers of atoms involved (e.g., H₂O for water).
Why is it necessary to balance chemical equations?
Balancing chemical equations ensures that the Law of Conservation of Matter is obeyed. It ensures that the same number of atoms of each element are present on both sides of the equation.
What is relative atomic mass, and how is it determined?
Relative atomic mass is the average mass of an atom of an element compared to 1/12th of the mass of a carbon-12 atom. It accounts for the presence of different isotopes and their relative abundances.
What is the mole concept, and how is it used in chemistry?
The mole is a fundamental unit in chemistry representing 6.022 x 10²³ particles (atoms, molecules, ions, etc.). It is used to relate the mass of a substance to the number of particles it contains.
What is Avogadro’s number, and how is it used?
Avogadro’s number, 6.022 x 10²³, is the number of particles in one mole of a substance. It allows chemists to convert between the number of particles and the amount of substance in moles.
How do you calculate the amount of product formed in a reaction using stoichiometry?
To calculate the amount of product, first write and balance the chemical equation. Then, use the mole ratio from the balanced equation to convert the moles of reactants to moles of products, and finally convert moles of products to grams using molar mass if needed.
How do you calculate the molar mass of a compound?
To calculate molar mass, sum the atomic masses of all atoms in the compound’s chemical formula. For example, the molar mass of H₂O is calculated as 2(1.01 g/mol) + 16.00 g/mol = 18.02 g/mol.
How do you convert mass to moles using molar mass?
Moles = Mass (g) ÷ Molar mass (g/mol). For example, to find the moles in 58.44g of NaCl, calculate: Moles = 58.44 g ÷ 58.44 g/mol = 1 mole.
How do you convert moles of a substance to the number of particles?
Use Avogadro’s number: Number of particles = Number of moles × 6.022 × 10²³ particles/mol.
