Match the prefix used in naming binary molecule compounds with its corresponding number

what mass of sodium fluoride (FW=42.0 g/mol) must be added to 3.50 x 10^2 mL of water to give a solution with pH = 8.40?

MaRussiya [10]

Answer:

Explanation:

Sodium fluoride, being a salt, dissolves in water completely producing F ⁻ ions. Now F⁻ is the conjugate base of the weak acid HF, so in water we will have the following equilibrium:

F⁻ + H₂O ⇆ HF + OH⁻

Given this equilibrium, we need to calculate Kb from the Ka for HF, the [ OH ⁻] from the given pH, and finally the mass needed to produce that OH⁻ concentration.

The equilibrium constant, Kb , can be calculated from Kw = Ka x Kb, where Kw = 10⁻¹⁴ and Ka for HF is 6.6 x 10⁻⁴ from reference tables.

Kb = 10⁻¹⁴ / 6.6 x 10⁻⁴ = 1.5 x 10⁻¹¹

pH + pOH = 14 ⇒ pOH = 14 - 8.40 = 5.60

[ OH⁻ ] = 10^-5.60 = 2.51 x 10⁻⁶

Now we have all the information :

F⁻ HF OH⁻

Equilibrium X 2.51 x 10⁻⁶ 2.51 x 10⁻⁶

(2.51 x 10⁻⁶)² / X = 1.5 x 10⁻¹¹ ⇒ X = (2.51 x 10⁻⁶)² / 1.5 x 10⁻¹¹

X = [ F⁻ ] = 0.41 M

For 350 mL ( 0.35 L ) we need to add:

0.41 mol HF/ 1 L * 0.35 L = 0.144 mol

and finally the mass will be:

0.144 mol NaF * 42.0 g/mol NaF = 6.03 g NaF

7 0

3 years ago

Earnest Rutherford discovered that the nucleus is this

Nikitich [7]

Rutherford, through his gold-foil experiment, discovered that the nucleus is a small core of protons and neutrons making up most of the atom’s mass.

8 0

3 years ago

What’s the anwser ????????????????????

nevsk [136]

The oxidation state of N changes from +2 to 0 while that of C changed from +2 to +4.

<h3>Oxidation and reduction</h3>

Oxidation is defined as an increase in oxidation number of the addition of oxygen while reduction is a decrease in oxidation number or removal of oxygen.

In the reaction shown by the equation, the oxidation number of N in NO changed from +2 to 0 in $N_2$ while that of C in CO changed from +2 to +4 in $CO_2$ .

Thus, NO is acting as the oxidizing agent while CO is acting is the reducing agent.

More on oxidation and reduction can be found here: brainly.com/question/13699873

#SPJ1

4 0

2 years ago

Read 2 more answers

Starting with acetylene and bromoethane, show how you would use reagents from the table to synthesize 4-methyl-3-hexanone. (ente

Lady_Fox [76]

I have provided the full reaction scheme for the synthesis of 4-methyl-3-hexanone from the reaction of acetylene and bromoethane. Acetylene is initially reacted with NaNH₂ which is a strong base that deprotonates the C-H of the acetylene which creates a carbon nucleophile which will then attack the electrophilic carbon containing the bromo in bromoethane. This is a simple sn2 substitution. Essentially an ethyl group is added to each side of the triple bond in acetylene.

With the 3-hexyne in hand, the triple bond is reduced using Lindlar's catalyst which will hydrogenate only to the alkene and stop. The 3-hexene is then reacted with a peroxycarboxylic acid which is used to epoxidize the alkene, to give the epoxide.

The epoxide is reacted with the grignard reagent which treats the methyl as a strong nucleophile. The methyl adds to one carbon of the epoxide and opens the ring. The acid is added at the end to protonate the alcohol.

Finally, the alcohol is oxidized with chromic acid which will oxidize a secondary alcohol to the ketone. The final product is 4-methyl-3-hexanone.

7 0

3 years ago

What would the products of a double-replacement reaction between AgNO3

Radda [10]

Answer:

D. AgCl and KNO₃

Explanation:

anions switch from the original reaction.

8 0

3 years ago