1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Elena L [17]
2 years ago
14

Answer the following questions:

Chemistry
2 answers:
Y_Kistochka [10]2 years ago
8 0
Recrystallization is a technique used to purify chemicals, it's used for solid compounds most
Vera_Pavlovna [14]2 years ago
4 0

Answer:

fdfdgiukjgrguhjnfvthhhdqddwsvhjjj

You might be interested in
Glycolic acid, which is a monoprotic acid and a constituent in sugar cane, has a pKa of 3.9. A 25.0 mL solution of glycolic acid
Phoenix [80]

Answer:

pH = 8.0

Explanation:

First, we have to calculate the moles of NaOH.

35.8 \times 10^{-3}L.\frac{0.020mol}{L} =7.2\times 10^{-4}mol

Let's consider the balanced equation.

C₂H₄O₃ + NaOH ⇒ C₂H₃O₃Na + H₂O

The molar ratio C₂H₄O₃: NaOH: C₂H₃O₃Na is 1: 1: 1. So, when 7.2 × 10⁻⁴ moles of NaOH react completely with 7.2 × 10⁻⁴ moles of C₂H₄O₃ they form 7.2 × 10⁻⁴ moles of C₂H₃O₃Na.

The concentration of C₂H₃O₃Na is:

\frac{7.2\times 10^{-4}mol}{60.8 \times 10^{-3}L} =0.012M

C₂H₃O₃Na dissociates according to the following equation:

C₂H₃O₃Na(aq) ⇒ C₂H₃O₃⁻(aq) + Na⁺(aq)

C₂H₃O₃⁻ comes from a weak acid so it undergoes basic hydrolisis.

C₂H₃O₃⁻ + H₂O ⇄ C₂H₄O₃ + OH⁻

If we know that pKa for C₂H₄O₃ is 3.9, we can calculate pKb for C₂H₃O₃⁻ using the following expression:

pKa + pKb = 14

pKb = 14 -3.9 = 10.1

10.1 = -log Kb

Kb = 7.9 × 10⁻¹¹

We can calculate [OH⁻] using the following expression:

[OH⁻] = √(Kb.Cb)               <em>where Cb is the initial concentration of the base</em>

[OH⁻] = √(7.9 × 10⁻¹¹ × 0.012M) = 9.7 × 10⁻⁷ M

Now, we can calculate pOH and pH.

pOH = -log [OH⁻] = -log (9.7 × 10⁻⁷) = 6.0

pH + pOH = 14

pH = 14 - pOH = 14 - 6.0 = 8.0

7 0
3 years ago
in the future, clean energy sources, such as solar power, may be used to create hydrogen fuel true false
borishaifa [10]
False, b/c you can't turn electricity into a fuel 
3 0
3 years ago
Read 2 more answers
What is the molarity of a solution containing 8.9 g of NaOH in 550. mL of NaOH solution?
bulgar [2K]

Answer:

0.4 M

Explanation:

Molarity is defined as moles of solute, which in your case is sodium hydroxide,  

NaOH

, divided by liters of solution.

molarity

=

moles of solute

liters of solution

Notice that the problem provides you with the volume of the solution, but that the volume is expressed in milliliters,  

mL

.

Moreover, you don't have the number of moles of sodium hydroxide, you just have the mass in grams. So, your strategy here will be to

determine how many moles of sodium hydroxide you have in that many grams

convert the volume of the solution from milliliters to liters

So, to get the number of moles of solute, use sodium hydroxide's molar mass, which tells you what the mass of one mole of sodium hydroxide is.

7

g

⋅

1 mole NaOH

40.0

g

=

0.175 moles NaOH

The volume of the solution in liters will be

500

mL

⋅

1 L

1000

mL

=

0.5 L

Therefore, the molarity of the solution will be

c

=

n

V

c

=

0.175 moles

0.5 L

=

0.35 M

Rounded to one sig fig, the answer will be

c

=

0.4 M

Explanation:

6 0
3 years ago
Please help,<br> How could you tell a Ca(NO3)2 solution from a Zn(NO3)2 solution?
tamaranim1 [39]

Answer:

you better give me brainliest

Explanation:

Zinc nitrate and calcium nitrate solution can be distinguished by reaction with ammonium hydroxide. Zinc forms a white gelatinous ppt. whereas there is no precipitation of calcium hydroxide even with excess of ammonium hydroxide

3 0
1 year ago
What the atmosphere mean
Alex_Xolod [135]
The envelope of gases surrounding the earth or another planet.
3 0
4 years ago
Other questions:
  • Write the formula unit and the net-ionic equations to describe the reaction between potassium hydrogen phthalate (khp) and cesiu
    11·2 answers
  • What is the temperature of 0.750 mol of a gas stored in a 6,850 mL cylinder at 2.21 atm? Use PV=nRT and R=0.0821 (L•atm)/(mol•K)
    10·2 answers
  • Select the phrase that completes each statement. • Honey is . • Grape juice is • Sand on the beach is . • A mixture of carbon di
    8·1 answer
  • What evidence do you have that atoms of certain elements produce a flame of a specific color?
    14·1 answer
  • If an atom has 17 protons and 18 neutrons, what is the charge of the atom's nucleus?​
    15·1 answer
  • The modern atomic model includes electrons orbiting the nucleus. which of the following parts of dalton's atomic model was dispr
    5·1 answer
  • 1,670,000,000 in<br> scientific notation pleaseeee
    8·2 answers
  • Adiabatic process is a process in which _ is constant (a) temperature (b)volume (c)pressure (d) heat
    7·1 answer
  • Which of these expressions are correct variations of the Combined Gas Law?
    11·1 answer
  • Which factor would be most likely to shirk the size of an atom’s electronic cloud
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!