Separate chemistry 1 Study Guide

Avogadro’s law states that equal volumes of all gases, measured under the same temperature and pressure, contain equal numbers of molecules. In chemical reactions involving gases, this means that the ratios of the stoichiometric coefficients in the balanced equation can be directly applied to volume ratios. Therefore, if two gases react in a 1:2 ratio, one volume of the first gas will react with two volumes of the second gas (provided both are measured at the same conditions). This allows us to calculate unknown gas volumes involved in reactions by simply using the balanced equation's coefficients as volume ratios, avoiding the need to convert to and from moles during the calculation.

Pure metals typically have a regular, ordered arrangement of atoms, often described as a lattice structure. When a stress is applied to a pure metal, layers of atoms can slide past each other relatively easily due to this uniform arrangement. This sliding movement allows the metal to deform. Alloying involves adding one or more different elements to a pure metal. These added elements, frequently other metals, have atoms of different sizes compared to the host metal atoms. When these foreign atoms are introduced into the lattice structure, they disrupt the regular arrangement of the host metal atoms. This disruption creates irregularities within the crystal lattice. These irregularities act as obstacles, making it much more difficult for layers of atoms to slide past each other. Consequently, more force is required to deform the alloy, which means the alloy is stronger and less ductile than the pure metal from which it was formed. The 'model' here refers to the atomic arrangement and how different-sized atoms interfere with the movement of atomic layers.