Name and Title:

A solution is prepared by dissolving 0.26 mol of hydrazoic acid and 0.26 mol of sodium azide in water sufficient to yield 1.00 L

Pavel [41]

Answer:

The pH does not decrease drastically because the HCl reacts with the sodium azide (NaN₃) present in the buffer solution.

Explanation:

The buffer solution is formed by 0.26 moles of the weak acid, hydrazoic acid (HN₃), and by 0.26 moles of sodium azide (NaN₃). The equilibrium reaction of this buffer solution is the following:

HN₃(aq) + H₂O(l) ⇄ N₃⁻(aq) + H₃O⁺(aq)

The pH of this solution is:

$pH = pka + log(\frac{[N_{3}^{-}]}{[HN_{3}]}) = -log(2.5 \cdot 10^{-5}) + log(\frac{0.26 mol/1 L}{0.26 mol/1 L}) = 4.60$

When 0.05 moles of HCl is added to the buffer solution, the following reaction takes place:

H₃O⁺(aq) + N₃⁻(aq) ⇄ HN₃(aq) + H₂O(l)

The number of moles of NaN₃ after the reaction with HCl is:

$\eta_{NaN_{3}} = \eta_{i} - \eta_{HCl} = 0.26 moles - 0.05 moles = 0.21 moles$

Now, the number of moles of HN₃ is:

$\eta_{HN_{3}} = \eta_{i} + \eta_{HCl} = 0.26 moles + 0.05 moles = 0.31 moles$

Then, the pH of the buffer solution after the addition of HCl is:

$pH = pka + log(\frac{[N_{3}^{-}]}{[HN_{3}]}) = -log(2.5 \cdot 10^{-5}) + log(\frac{0.21 mol/V_{T}}{0.31 mol/V_{T}}) = 4.43$

The pH of the buffer solution does not decrease drastically, it is 4.60 before the addition of HCl and 4.43 after the addition of HCl.

Therefore, the pH does not decrease drastically because the HCl reacts with the sodium azide (NaN₃) present in the buffer solution.

I hope it helps you!

6 0

3 years ago

What is the molecule shown below?

arsen [322]

Answer:

2,3 -Dimethyl pentane

Explanation:

The given molecule is 2,3-Dimethyl pentane.

First of all select the longest chain of C-C atom. This will be the parent name.

In given structure the longest chain is straight chain that contain five carbon. Thus the parent name will pentane and there is no double or triple bond the given structure is of alkane.

Than locate the positions of functional groups attached.

In given structure there are two methyl groups are present. Give the name in such a way that functional groups will have lowest number. In given case we will start from the left.

The first methyl group will have number 2 and second will have number 3.

The name will be,

2,3-Dimethyl pentane

8 0

3 years ago

The overall force on an object is called the:

shusha [124]

Answer: D

Explanation:

Balanced force is when 2 equal forces are acting on each other, summing force isn’t a thing, unbalanced force is when 2 unequal forces are acting on each other, and net force is the total amount of forces acting on an object. Hope this helps!

8 0

4 years ago

Read 2 more answers

Describe the process used to measure out a specific mass of a solid.

Andre45 [30]

You first weigh you're solid to determine it's mass. Then put it in a container that has liquid with definite volume which can't dissolve solid, absolutely when you put solid in liquid, liquid raise and you have volume of solid. 
specificmass=mass/volume

6 0

3 years ago

How does the density of a Hershey bar compare to the density of the a half bar?How does the density of a Hershey bar compare to

Lostsunrise [7]

IDensity is calculated by mass divided by volume. As you half the Hershey bar, mass and volume change by the same proportion. Therefore, density is the same.

3 0

3 years ago