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
antiseptic1488 [7]
3 years ago
8

A 0.7834 g sample of a primary standard KHP was titrated with 38.45 mL of NaOH solution to a phenolphthalein end-point. What is

the molarity of the NaOH solution?
Chemistry
1 answer:
Zinaida [17]3 years ago
6 0

Answer:

0.0998 M

Explanation:

KHP is a weak <em>monoprotic</em> acid. This means that t<u>he moles of acid are equal to the moles of OH⁻ that were added in the titration</u>.

KHP Molecular weight = 204.22 g/mol

  • moles KHP = 0.7834 g ÷ 204.22 g/mol = 3.836x10⁻³ mol KHP

So  3.836x10⁻³ moles of OH⁻ were added in the titration. With moles and volume we can <u>calculate the molarity of the NaOH solution</u>:

38.45 mL ⇒ 38.45/1000 = 0.03845 L

  • 3.836x10⁻³ mol OH⁻ / 0.03845 L = 0.0998 M
You might be interested in
NEED HELP ASAPPP<br><br> What is the number of beryllium atoms in 78.0g of Be?
polet [3.4K]

Answer: number of atoms is 5.21 · 10^24

Explanation: Atomic mass of Be is 9.012 g/mol.

Number of moles n = m/M = 78.0 g / 9.012 g/mol =

Multiply this with Avogadro number Na = 6.022*10^23 1/mol

4 0
3 years ago
How many moles of oxygen are contained in. 752 moles of calcium carbonate?
Nitella [24]

Answer:

2.256 moles of oxygen atoms

Explanation:

CaCo3  is calcium carbonate

  every mole of calc carb has 3 moles of O atoms

  .752 moles of this has 3 times as many moles of Oxygen atoms

4 0
2 years ago
The muscles in the stomach aid in digestion by __________.
dsp73

Churning or mixing food.

The stomach is a muscular sac that lies between theesophagus and thesmall intestine in the upper abdomen. The stomach is not the only part of your digestive system that absorbs food but rather is a part of the digestive system and important for churning food into a consistency that is easier to digest for the rest of your intestines.

4 0
3 years ago
Read 2 more answers
For Na2HPO4:(( (Note that for H3PO4, ka1= 6.9x10-3, ka2 = 6.4x10-8, ka3 = 4.8x10-13 ) a) The active anion is H2PO4- b) The activ
Komok [63]

Answer:

Check the explanation

Explanation:

Answer – Given, H_3PO_4 acid and there are three Ka values

K_{a1}=6.9x10^8, K_{a2} = 6.2X10^8, and K_{a3}=4.8X10^{13}

The transformation of H_2PO_4- (aq) to HPO_4^2-(aq)is the second dissociation, so we need to use the Ka2 = 6.2x10-8 in the Henderson-Hasselbalch equation.

Mass of KH2PO4 = 22.0 g , mass of Na2HPO4 = 32.0 g , volume = 1.00 L

First we need to calculate moles of each

Moles of KH2PO4 = 22.0 g / 136.08 g.mol-1

                             = 0.162 moles

Moles of Na2HPO4 = 32.0 g /141.96 g.mol-1

                             = 0.225 moles

[H2PO4-] = 0.162 moles / 1.00 L = 0.162 M

[HPO42-] = 0.225 moles / 1.00 L = 0.225 M

Now we need to calculate the pKa2

pKa2 = -log Ka

       = -log 6.2x10-8

       = 7.21

We know Henderson-Hasselbalch equation

pH = pKa + log [conjugate base] / [acid]

pH = 7.21 + log 0.225 / 0.162

     = 7.35

The pH of a buffer solution obtained by dissolving 22.0 g of KH2PO4 and 32.0 g of Na2HPO4 in water and then diluting to 1.00 L is 7.35

6 0
3 years ago
(Paper Chromatography)
allsm [11]
1. The newspaper solution that would work best with inks is alcohol since alcohol can dissolve inks.
2. Water can be used to carry salts since salts are soluble in water.
3. Oils can be used to carry fatty acids since they're both hydrophobic substances.<span />
4 0
3 years ago
Other questions:
  • The second-order decomposition of NO2 has a rate constant of 0.255 M-15-1. How much NO2 decomposes in 4.00 s if the initial conc
    12·1 answer
  • Explain why two thin sweaters feel warmer then one thick sweater​
    10·1 answer
  • Why hydrogen fluoride is a gas at room temperature?
    14·1 answer
  • PLEASE HELP ME!
    7·2 answers
  • A sample of N2 gas occupied 9.20 L at 21 degrees C and 0.959 atm. If the pressure is tuned to 1.15 atm at constant temperature w
    6·1 answer
  • 2. What type of element is most abundant: metals, nonmetals, or metalloids
    5·2 answers
  • How many total atoms are in v2o5
    6·1 answer
  • PLEASE HELP WILL GIVE BRAINLIEST
    12·1 answer
  • The term "cycle" is used in Water Cycle because ?
    5·1 answer
  • What does the photoelectric effect prove?
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!