Final answer:
By using the molar volume of gas at STP, the molar mass of the noble gas is calculated to be approximately 20.17 g/mol, which closely matches the molar mass of neon (Ne).
Step-by-step explanation:
The student asks at STP (Standard Temperature and Pressure), what noble gas corresponds to a sample that has a mass of 12.69 grams and occupies a volume of 14.09 L. To determine the identity of the noble gas, we can use the molar volume concept and the idea that one mole of any gas at STP occupies 22.4 L. Using these principles, we calculate the molar mass of the unknown noble gas.
First, we find the amount in moles of the gas using its volume: moles = 14.09 L / 22.4 L/mol = 0.629 moles. Next, we calculate the molar mass: molar mass = mass / moles = 12.69 g / 0.629 moles = 20.17 g/mol. This molar mass closest matches the molar mass of neon (Ne), which is approximately 20.18 g/mol, amongst the given options.