Answer: 20.0 g of hydrogen chloride must simultaneously be formed
Explanation:
The balanced chemical reaction is :

According to the law of conservation of mass, mass can neither be created nor be destroyed. The mass on reactant side must be equal to the mass on product side.
Thus mass of reactants = mass of products
Given : mass of ammonium chloride = mass of reactants = 29.4 g
mass of ammonia = 9.4 g
mass of products = mass of ammonia + mass of hydrogen chloride
9.4 g +mass of hydrogen chloride = 29.4 g
mass of hydrogen chloride = 20.0 g
Answer:
Option B. is the right answer.
Explanation:
Before developing a new technology, an engineer has to evaluate the advantages and disadvantages of the chemical used in order to clean water bodies. If the chemical has more disadvantages as compared to advantages, so its usage will be avoided while if the chemical does not harm the marine organisms of the ocean so it can be used for the purpose of cleaning. So we can say that first the engineer has to study the chemicals.
Answer : The activation energy of the reaction is, 
Solution :
The relation between the rate constant the activation energy is,
![\log \frac{K_2}{K_1}=\frac{Ea}{2.303\times R}\times [\frac{1}{T_1}-\frac{1}{T_2}]](https://tex.z-dn.net/?f=%5Clog%20%5Cfrac%7BK_2%7D%7BK_1%7D%3D%5Cfrac%7BEa%7D%7B2.303%5Ctimes%20R%7D%5Ctimes%20%5B%5Cfrac%7B1%7D%7BT_1%7D-%5Cfrac%7B1%7D%7BT_2%7D%5D)
where,
= initial rate constant = 
= final rate constant = 
= initial temperature = 
= final temperature = 
R = gas constant = 8.314 kJ/moleK
Ea = activation energy
Now put all the given values in the above formula, we get the activation energy.
![\log \frac{8.75\times 10^{-3}L/mole\text{ s}}{4.55\times 10^{-5}L/mole\text{ s}}=\frac{Ea}{2.303\times (8.314kJ/moleK)}\times [\frac{1}{468K}-\frac{1}{531K}]](https://tex.z-dn.net/?f=%5Clog%20%5Cfrac%7B8.75%5Ctimes%2010%5E%7B-3%7DL%2Fmole%5Ctext%7B%20s%7D%7D%7B4.55%5Ctimes%2010%5E%7B-5%7DL%2Fmole%5Ctext%7B%20s%7D%7D%3D%5Cfrac%7BEa%7D%7B2.303%5Ctimes%20%288.314kJ%2FmoleK%29%7D%5Ctimes%20%5B%5Cfrac%7B1%7D%7B468K%7D-%5Cfrac%7B1%7D%7B531K%7D%5D)

Therefore, the activation energy of the reaction is, 
Hey there,
A scientist triples the temperature of a gas at constant pressure. By what factor does the gas’s volume change?
I believe that when the scientist triples the temperature of the gas at a certain and constant pressure, the factor of the gas volume would change most likely with the double amount of pressure that the scientist put in the first place.
~Jurgen