You're asking about the root-mean-square (rms) speed of atoms in a gas mixture of neon and argon. Here's how to approach this problem:

Understanding RMS Speed

The rms speed of gas particles is a measure of their average kinetic energy. It's related to the temperature of the gas and the molar mass of the gas particles by the following equation:

* v_rms = √(3RT/M)

where:

* v_rms is the root-mean-square speed (in m/s)

* R is the ideal gas constant (8.314 J/mol·K)

* T is the temperature (in Kelvin)

* M is the molar mass of the gas (in kg/mol)

The Problem

You've provided the rms speed (350 m/s) but haven't given the temperature. This makes it impossible to directly determine the molar mass of the gas mixture.

Here's why:

* The rms speed is influenced by both temperature and molar mass. A higher temperature leads to higher rms speed, and a lower molar mass also leads to higher rms speed.

* Without the temperature, we can't isolate the molar mass.

How to Solve with More Information

To find the molar mass (and thus the composition of the gas mixture) you would need either:

1. The temperature: With the temperature, you can use the rms speed equation to calculate the molar mass.

2. The relative abundance of neon and argon: You could use the known molar masses of neon (20.18 g/mol) and argon (39.95 g/mol) to calculate the average molar mass of the mixture based on their proportions.

Let me know if you have either the temperature or the relative abundance of neon and argon, and I can help you calculate the composition of the gas mixture!