Remember that:
number of moles = mass/molar mass
First, we get the molar mass of the nitrogen gas molecule:
It is known the the nitrogen gas is composed of two nitrogen atoms, each with molar mass 14 gm (from the periodic table)
Therefore, molar mass of nitrogen gas = 14 x 2 = 28 gm
Second we calculate the mass of the precipitate:
we have number of moles = 0.03 moles (given)
and molar mass = 28 gm (calculated)
Using the equation mentioned before,
mass = number of moles x molar mass = 0.03 x 28 = 0.84 gm
Answer:
c The concentration(s) of reactant(s) is constant over time.
Step-by-step explanation:
When the reaction A ⇌ B reaches equilibrium, the concentrations of reactants and products are constant over time.
a is <em>wrong</em>, because the concentrations of reactants and products are usually quite different.
b is <em>wrong</em>, because both product and reactant molecules are being formed at equilibrium.
d is <em>wrong</em>. The rates of the forward and reverse reactions are equal, but they are not zero.
ANSWERS:
1.

⇒ 2KCl +

2.

⇒

3.

⇒

4.

⇒

5.

⇒

I have attached my work for 1-3. I would like to see if you can get 4 and 5 on your own. but, if you are struggling/copnfused please let me know in the comments! :)