Rank in order of decreasing average molecular speed at 21 degrees celsius: Ne, HBr, SO2, NF3, CO
To rank the substances in order of decreasing average molecular speed at 21 degrees Celsius, we need to consider their molecular mass and temperature.
The average molecular speed of a gas is directly proportional to its temperature and inversely proportional to the square root of its molar mass.
The molecular mass of each substance is as follows:
Ne (Neon): 20.18 g/mol
HBr (Hydrogen Bromide): 80.91 g/mol
SO2 (Sulfur Dioxide): 64.06 g/mol
NF3 (Nitrogen Trifluoride): 71.00 g/mol
CO (Carbon Monoxide): 28.01 g/mol
Since all substances are at the same temperature of 21 degrees Celsius, the average molecular speed will primarily be determined by their molar masses.
Ranking the substances from highest to lowest average molecular speed:
1. Ne (Neon): With the lowest molar mass, Neon will have the highest average molecular speed.
2. CO (Carbon Monoxide): Although it has a higher molar mass, it is still relatively low compared to the other molecules.
3. NF3 (Nitrogen Trifluoride): The molar mass of NF3 is higher than CO but lower than the remaining compounds.
4. SO2 (Sulfur Dioxide): Slightly heavier than NF3.
5. HBr (Hydrogen Bromide): With the highest molar mass among the substances listed, HBr will have the lowest average molecular speed.
So, the ranking in order of decreasing average molecular speed at 21 degrees Celsius is:
1. Ne
2. CO
3. NF3
4. SO2
5. HBr