<span>Pre-1982 definition of STP: 37 g/mol
Post-1982 definition of STP: 38 g/mol
This problem is somewhat ambiguous because the definition of STP changed in 1982. Prior to 1982, the definition was 273.15 K at a pressure of 1 atmosphere (101325 Pascals). Since 1982, the definition is 273.15 K at a pressure of exactly 100000 Pascals). Because of those 2 different definitions, the volume of 1 mole of gas is either 22.414 Liters (pre 1982 definition), or 22.71098 liters (post 1982 definition). And finally, there's entirely too many text books out there that still use the 35 year obsolete definition. So let's solve this problem using both definitions and you need to pick the correct answer for the text book you're using.
First, determine how many moles of gas you have. Just simply divide the volume you have by the molar volume.
Pre-1982: 2.1 / 22.414 = 0.093691443 moles
Post-1982: 2.1 / 22.71098 = 0.092466287 moles
Now determine the molar mass. Simply divide the mass by the moles. So
Pre-1982: 3.5 g / 0.093691443 moles = 37.35666667 g/mol
Post-1982: 3.5 g / 0.092466287 moles = 37.85163333 g/mol
Finally, round to 2 significant figures. So
Pre-1982: 37 g/mol
Post-1982: 38 g/mol</span>
Exothermic reaction is when the system releases energy to the surrounding, the energy (in the perspective of the system) will have a sign of negative, as the system is transferring energy towards the surrounding.
Endothermic reaction is when the system is absorbing energy from the surrounding, the energy (in the perspective of the system) will have a sign of positive, as energy is transferred to the system.
1. Energy can neither be created or destroyed.
2. Conduction. Putting a pot of water on a hot burner. Convection. Putting your wet shoes over an air vent to dry them quicker. Radiation. Sitting in front of the fire to warm your hands up.
3. renewable sources can be used again and again, but non renewable sources cannot.
4. I would recommend solar energy. I think solar energy should be considered because solar energy can be reused, and also because they can use it to power their houses and they wouldn't need fossil fuels to do so.
5. Turn off the lights and open the windows during the day and if something is left plugged into the wall and it is not being used, unplug it.
hope I could help!
Answer:
it will float back up because it's not dense enough to go down
<span>The wave nature of an electron is indicated by its motion and the diffraction and interference of electrons in a beam.</span>
