Answer:
0.26 moles........................
The most common way of preventing bumping is by adding one or two boiling chips to the reaction vessel. However, these alone may not prevent bumping and for this reason it is advisable to boil liquids in a boiling tube, a boiling flask, or an Erlenmeyer flask.
It is softer than topaz and and it is softer than diamond (diamond has a Mohs hardness of 10, which is the highest value of the scale)
Answer:Vrms is 149.7266 m/sec
Explanation:The root means square velocity of a gas can be calculated as follows:
Vrms =

where:
R is the ideal gas constant = 8.3145
T is absolute temperature = -55 + 273 = 118 degrees kelvin
M is the molar mass of the gas = 131.293 grams = 0.131293 kg
Substituting with these givens in the above equation, we would find that the Vrms is 149.7266 m/sec
Hope this helps :)
I know for number 4 the answer is c, sorry I can't help with the others.