Answer:
2HCl is the product of this reaction 2 is added in order to balance the reaction
The chemical reaction that the situation demonstrates would be a double replacement reaction.
In double replacement reactions, the two reactants participating in the reaction are similarly built in terms of their chemical bonds and they exchange ions to form the products of the reaction. Two products are also formed from the two reactants.
It is as opposed to single replacement reactions in which the two reactants are not similar bond-wise. One of the reactants replaces or displaces one of the ions in another reactant.
In this case, the situation can be represented as follows:
Amanda-Janice + Deja-Eden ----> Amanda-Eden + Deja-Janice
Thus, it is a form of double replacement reaction.
More on double replacement reactions can be found here: brainly.com/question/392491?referrer=searchResults
Answer : The correct option is, (B) 
Solution :
According to the Graham's law, the rate of effusion of gas is inversely proportional to the square root of the molar mass of gas.

or,
..........(1)
where,
= rate of effusion of unknown gas = 
= rate of effusion of oxygen gas = 
= molar mass of unknown gas = ?
= molar mass of oxygen gas = 32 g/mole
Now put all the given values in the above formula 1, we get:


The unknown gas could be carbon dioxide
that has approximately 44 g/mole of molar mass.
Thus, the unknown gas could be carbon dioxide 
Answer:
160.9 mol ≅ 161.0 mol.
Explanation:
- It is known that every 1.0 mole of compound or element contains Avogadro's number (6.022 x 10²³) of molecules or atoms (formula units).
Using cross multiplication:
1.0 mole of Fe(NO₃)₃ contains → 6.022 x 10²³ formula units.
??? mole of Fe(NO₃)₃ contains → 9.69 x 10²⁵ formula units.
<em>∴ The no. of moles of He contains (9.69 x 10²⁵ formula units)</em> = (1.0 mol)(9.69 x 10²⁵ formula units.)/(6.022 x 10²³ formula units) = <em>160.9 mol ≅ 161.0 mol.</em>