Answer:
It is an example of Exothermic reaction.
Explanation:
It leads to release of HEAT as can be seen water is given in gaseous form.
<span>A chemist adds 155.0ml of a 4.10 X 10^-5 mmol/L of a zinc oxalate (ZnC2O4)solution to a reaction flask. Calculate the mass in micrograms of zinc oxalate the chemist has added to the flask.
1mmol = 10^-3 mol
Therefore 4.10*10^-5mmol = 4.10*10^-8mol
molar mass ZnC2O4 = 65.39+(2*12.011)+(4*15.99) = 153.372g/mol
You have 4.10*10^-8 mol/litre =153.372 * 4.10*10^-8 = 6.29*10^-6 grams / litre (* see below)
But you have 155ml. Mass of ZnC2O4 = 155/1000*6.29*10^-6 g
Mass is = 9.75*10^-7 grams
1µg = 10^-6 g
You then have 9.75*10^-7/10^-6 = 0.975µg ZnC2O4
(*see below) at this point you could have said:
1µg = 10^-6 g therefore you have a solution of 6.29µg per litre,
155ml = 6.29*155/1000 = 0.975µg ZnC2O4</span>
Answer: 0.0345 sec
Explanation:
Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
![Rate=k[H_3PO_4]^2](https://tex.z-dn.net/?f=Rate%3Dk%5BH_3PO_4%5D%5E2)
k= rate constant = ![46.6s^{-1}](https://tex.z-dn.net/?f=46.6s%5E%7B-1%7D)
Expression for rate law for first order kinetics is given by:
![t=\frac{2.303}{k}\log\frac{a}{a-x}](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B2.303%7D%7Bk%7D%5Clog%5Cfrac%7Ba%7D%7Ba-x%7D)
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
for completion of 20 % of reaction
![t=\frac{2.303}{46.6}\log\frac{0.660}{\frac{20}{100}\times 0.660}](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B2.303%7D%7B46.6%7D%5Clog%5Cfrac%7B0.660%7D%7B%5Cfrac%7B20%7D%7B100%7D%5Ctimes%200.660%7D)
![t=\frac{2.303}{46.6}\log\frac{0.660}{0.132}](https://tex.z-dn.net/?f=t%3D%5Cfrac%7B2.303%7D%7B46.6%7D%5Clog%5Cfrac%7B0.660%7D%7B0.132%7D)
![t=0.0345sec](https://tex.z-dn.net/?f=t%3D0.0345sec)
The time taken for the concentration of
to decrease to 20% to its natural value is 0.0345 sec
Answer:
Mass of Nacl = 4.92 gram (Approx)
Explanation:
Given:
Hydrochloric acid = 3.3 g
Sodium hydroxide = 5 g
Computation:
Hcl + NaoH ⇒ Nacl + H₂O
Number of mole of Hcl = 3.3 / 36.46 = 0.0905 moles
Number of mole of NaoH = 5 / 40 = 0.125 moles
We, know that number of moles in Hcl is less then number of mole in NaoH
So,
Number of mole of Hcl = Number of mole of Nacl
So,
Mass of Nacl = Number of mole of Nacl × Molar mass of Nacl
Mass of Nacl = 0.0905 × 54.4
Mass of Nacl = 4.92 gram (Approx)