Answer is: <span>the molecular mass ratio of two gases is 1 : 256.
</span>rate of effusion of
gas1 : rate of effusion of gas = 16 : 1.<span>
rate of effusion of gas1 = 1/√M(gas1).
rate of effusion of gas2 = 1/√M(gas2).
rate of effusion of gas1 = rate of
effusion of gas2 </span>· 16<span>.
</span>1/√M(gas1) = 1/√M(gas2) · 16 /².
<span>1/M(gas1) = 1/M(gas2) </span>· 256.
<span>M(gas1) </span>· 256 = M(gas2).<span>
</span>
Answer: I believe the 1st and 3rd reactions are better obtained through reference sources and the 2nd and 4th are easiest and safest to measure in the laboratory.
Explanation:
I am also working on this Pre-lab right now, and I looked back at the first question to help get my answer. In the first question (a), it is noted that ammonia gas and gaseous hydrochloric acid are both potentially dangerous in gaseous form. I saw that both the 1st and 3rd reactions contained noxious gases (I knew this because there was a (g) in both of these reactions). Using the knowledge from the first question that the noxious gases were potentially dangerous, I assumed that those reactions were the ones that are better obtained through the reference sources. The 2nd and 4th reactions did not contain any noxious gases, so I assumed those ones were easiest and safest to measure in the laboratory. Hope this helps!
The climatology method of forecasting uses averages to predict future weather.
Answer: B
Explanation
The satellites and advanced technologies have helped meteorologists to forecast accurately.
There are four types of forecasting methods prevailing now.
They are climatology method, persistence method, analog method and trends method.
The persistence and trends method uses the previous day forecast and compare with today's condition to forecast about future.
The analog method is a complex method where the forecasting is done by comparing present weather condition with a similar condition occurred in the past to predict for future.
The climatology is the simplest method which uses average of weather conditions observed in the previous days to get accurate forecast for future.
Answer: The molar solubility of barium fluoride is 0.0183 moles/liter.
Explanation:
The equation for the reaction will be as follows:

By Stoichiometry,
1 mole of
gives 2 moles of
and 1 mole of 
Thus if solubility of
is s moles/liter, solubility of
is s moles/liter and solubility of
is 2s moles/liter
Therefore,
![K_sp=[Ba^{2+}][F^{-}]^2](https://tex.z-dn.net/?f=K_sp%3D%5BBa%5E%7B2%2B%7D%5D%5BF%5E%7B-%7D%5D%5E2)
![2.45\times 10^{-5}=[s][2s]^2](https://tex.z-dn.net/?f=2.45%5Ctimes%2010%5E%7B-5%7D%3D%5Bs%5D%5B2s%5D%5E2)



Thus the molar solubility of barium fluoride is 0.0183 moles/liter.