Moles, Avogadro, and Molar Mass 2025/2026 Exam with Complete Solutions

Moles, Avogadro, and Molar Mass 2025/2026 Exam with Complete Solutions Activity: Moles, Avogadro, and Molar Mass Prior Knowledge Questions 1. In the image, note a dozen eggs, a dozen donuts and a dozen roses. How many of each item do you have? 12 eggs, 12 donuts, and 12 roses. 2. Would a dozen of each object have the same mass? No 3. Suppose you have a dozen silver atoms, a dozen oxygen atoms, and a dozen lithium atoms. Even though you have the same number of each, will they all have the same mass? Explain. They will not all have the same mass because although there may be an equal amount of each one, they don’t all weigh the same or take up the same amount of space. Gizmo Warm-up On the AVOGADRO CONSTANT tab, place the copper (Cu) atom on the nano-balance on the left, which will show the average atomic mass of copper rather than the mass of a single copper atom. 1. What is the average mass of a copper atom? 63.546 u The unit “u” refers to unified atomic mass units. (Officially, 1 u is one-twelfth the mass of a C-12 atom.) 2. To know how many atoms are in a gram of copper, use the larger balance on the right. Press Add atoms to put a scoop of atoms in the weighing dish, and keep adding until the balance registers between 1 and 2 grams. If you don’t seem to be making much progress, adjust the exponent using the slider, which will make the scoop size bigger.