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
Alexandra [31]
3 years ago
11

What is the purpose of adding phenolphthalein to your Erlenmeyer flask prior to starting a titration?

Chemistry
1 answer:
koban [17]3 years ago
3 0

Answer:

a. The phenolphthalein acts as a color changing indicator to signal the endpoint of the reaction.

Explanation:

Phenolphthalein is an organic substance with chemical formula C_{20}H_{14}O_{4}.

It is a substance commonly used in acid-base titrations to indicate the end point in the titration because phenolphthalein is colorless in acidic solutions but turns a purplish-pink color in basic solutions.

In this way it helps visually to notice when the final point of the titration has been reached.

You might be interested in
Calculate the molar solubility of PbBr2 (Ksp = 4.67x10-6) in 0.10M NaBr solution.
Softa [21]

Explanation:

PbBr_{2} will dissociate into ions as follows.

         PbBr_{2}(s) \rightleftharpoons Pb^{2+}(aq) + 2Br^{-}(aq)

Hence, K_{sp} for this reaction will be as follows.

                   K_{sp} = [Pb^{2+}][Br^{-}]^{2}

We take x as the molar solubility of PbBr_{2} when we dissolve x moles of solution per liter.

Hence, ionic molarities in the saturated solution will be as follows.

               [Pb^{2+}] = [Pb^{2+}]_{o} + x

               [Br^{-}]^{2} = [Br^{-}]_{o} + 2x

So, equilibrium solubility expression will be as follows.

            K_{sp} = ([Pb^{2+}]_{o} + x)([Br^{-}]_{o} + 2x)^{2}

Each sodium bromide molecule is giving one bromide ion to the solution. Therefore, one solution contains [Br^{-}]_{o} = 0.10 and there will be no lead ions. So, [Pb^{2+}]_{o} = 0

So, [Br^{-}]_{o} + 2x will approximately equals to [Br^{-}]_{o}.

Hence, K_{sp} = x[Br^{-}]^{2}_{o}

            4.67 \times 10^{-6} = x \times (0.10)^{2}

                        x = 4.67 \times 10^{-4} M

Thus, we can conclude that molar solubility of PbBr_{2} is 4.67 \times 10^{-4} M.

5 0
3 years ago
Read 2 more answers
Two processes of plant reproduction are described below.
Stells [14]

Answer:

Process 1 is pollination and Process 2 is germination

Explanation:

Pollination is the act of transferring pollen grains from the male anther of a flower to the female stigma. The goal of every living organism, including plants, is to create offspring for the next generation. One of the ways that plants can produce offspring is by making seeds.

Germination refers to the process by which an organism grows from a seed or a spore. The most common forms of germination include a seed sprouting to form a seedling and the formation of a sporeling from a spore. Thus, germination occurs primarily in plant and fungal species.

I hope this help :)

good luck

6 0
2 years ago
Read 2 more answers
A cooling curve has two flat lines, or plateaus. What does the plateau at the higher temperature represent?
blagie [28]

Answer:

It is in the state of "thermal arrest"

Explanation:

The temperature stays constant during the phase change process . This is because the matter has more internal energy and heat has to be taken away for the solidification process to begin. The energy that is required for a phase change is know as latent heat (which is the energy released or absorbed by a body during a thermodynamic process).

5 0
3 years ago
Read 2 more answers
What type of bonding holds the atoms in an h2o molecule together?
Ivanshal [37]
Covalent bond  two non metals
3 0
3 years ago
For each item, choose whether the change is a physical change or chemical change
Aleonysh [2.5K]

Sorry, but where are the ‘items’?

8 0
3 years ago
Other questions:
  • WILL MARK BRAINLIEST! ANSWER QUICKLY!!!!
    13·2 answers
  • ¿la densidad de una solución es mayor o menor al agregar agua?
    7·1 answer
  • Classify the following atom as excited, ground state, or not possible.<br><br> 1s^2 2s^2 2p^6 3p^1
    10·1 answer
  • Pick the TWO conversions which are exact.
    15·2 answers
  • Atoms bond because they become more ____ when they have ____ outer ______.
    12·1 answer
  • Elaine's teacher gave her two cubes and asked her to record as many observations as possible. The data table of her observations
    10·1 answer
  • A hydrogen filled balloon has a bolume of 8.3 L at 36 C and 751 torr. How many moles of hydrogen are inside the balloon?
    13·1 answer
  • mass number is the number of protons and neutrons in the nucleus of an isotope . how many protons in an oxygen-18 atom ?
    8·1 answer
  • The population that experienced the highest radioactivity from chernobyl in norway were:______
    9·1 answer
  • Acids, bases, and salts belong to a large group of compounds called:__________
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!