Answer :
Estimating the number of sand grains in 7 grams of sand involves a Chemistry concept called the mole, related to Avogadro's number. To answer precisely, the average mass of a single grain is needed, a detail not provided. The number of sand grains can vary depending on the grain size and density.
The subject of the question relates to estimating the number of grains of sand based on their mass. This is fundamentally a question rooted in Chemistry, specifically the topic of moles and Avogadro's number, which are central concepts in stoichiometry and material science.
From the provided information, one can infer a grain of sand is roughly 1 millimeter long and has a comparable mass to a paperclip, which is about 1 gram. If there are approximately 7.5 x 1018 grains of sand on Earth and this number constitutes a certain number of moles of sand grains, we might use a similar estimation process for the 7 grams of sand in the student's question.
However, to provide an accurate answer to the student's question, one would need additional information or assumptions, such as the average mass of a single grain of sand. Without this, one can only provide a very rough estimate based on the comparisons given. The actual number of sand grains in 7 grams would vary greatly with the size and density of individual sand grains, which can range in size from 0.063 mm (63 micrometers) to 2mm.
