Answer :
The time taken by the reaction is 19.2 seconds.
The order of reaction is, second order reaction.
Explanation :
The general formula to determine the unit of rate constant is:

Unit of rate constant Order of reaction
0
1
2
As the unit of rate constant is
. So, the order of reaction is second order.
The expression used for second order kinetics is:
![kt=\frac{1}{[A_t]}-\frac{1}{[A_o]}](https://tex.z-dn.net/?f=kt%3D%5Cfrac%7B1%7D%7B%5BA_t%5D%7D-%5Cfrac%7B1%7D%7B%5BA_o%5D%7D)
where,
k = rate constant = 
t = time = ?
= final concentration = 0.97 M
= initial concentration = 2.48 M
Now put all the given values in the above expression, we get:


Therefore, the time taken by the reaction is 19.2 seconds.
To convert the mass of a compound to formula units, the conversion factor is Avogadro's number, 6.022 x10^23 formula units/ mol and its molar mass. In this case, we are given with 19.0 grams of magnesium chloride which has a mass of 95.21 g/mol. Hence the answer is 1.20 x 10^23 formula units.
You can use P1V1/T1 = P2V2/T2 but since pressure is constant is becomes V1/T1=V2/T2
V1=0.5 L
T1=203 K
T2=273 K
V2=unknown
0.5L/203 = V2/273
V2= 0.67 L so C
Hope this helps :)
Answer:
A. Wipe down the glassware to remove any cleaning solvent.
Explanation:
· Remove stoppers and stopcocks when they are not in use. Otherwise, they may "freeze" in place. You can de-grease ground glass joints by wiping them with a lint-free towel soaked with ether or acetone. Wear gloves and avoid breathing the fumes. The deionized water rinse should form a smooth sheet when poured through clean glassware.