Ms. Block's students are studying chemical reactions. A classic reaction occurs when a metal is added to hydrochloric acid. Migu
2 answers:
<u>Answer:</u> The missing mass of 8 grams was of hydrogen.
<u>Explanation:</u>
Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.
This also means that total mass on the reactant side must be equal to the total mass on the product side.
The chemical equation for the reaction of magnesium metal and hydrochloric acid follows:
Let the mass of hydrogen gas be 'x' grams
We are given:
Mass of hydrochloric acid = 30 grams
Mass of magnesium metal = 30 grams
Mass of magnesium chloride = 52 grams
Total mass on reactant side = 30 + 30 = 60 g
Total mass on product side = 52 + x
So, by applying law of conservation of mass, we get:
The missing mass of 8 grams was the mass of hydrogen gas which was also formed in the reaction but got disappeared in the air.
Hence, the missing mass of 8 grams was of hydrogen.
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Hello!
The molarity of the HBr solution is 0,172 M.
Why?
The neutralization reaction between LiOH and HBr is the following:
HBr(aq) + LiOH(aq) → LiBr(aq) + H₂O(l)
To solve this exercise, we are going to apply the common titration equation:
Have a nice day!
Answer:
Equilibrium constant expression for :
.
Where
,
, and
denote the activities of the three species, and
,
, and
denote the concentrations of the three species.
Explanation:
<h3>Equilibrium Constant Expression</h3>The equilibrium constant expression of a (reversible) reaction takes the form a fraction.
Multiply the activity of each product of this reaction to get the numerator. is the only product of this reaction. Besides, its coefficient in the balanced reaction is one. Therefore, the numerator would simply be
.
Similarly, multiply the activity of each reactant of this reaction to obtain the denominator. Note the coefficient "" on the product side of this reaction.
is equivalent to
. The species
appeared twice among the reactants. Therefore, its activity should also appear twice in the denominator:
.
That's where the exponent "" in this equilibrium constant expression came from.
Combine these two parts to obtain the equilibrium constant expression:
.
In dilute solutions, the equilibrium constant expression can be approximated with the concentrations of the aqueous "" species. Note that all the three species here are indeed aqueous. Hence, this equilibrium constant expression can be approximated as:
.