1. A student performed the titration as in this experiment. He transferred a 2.00 mL sample of the

acid into a flask, diluted it with water, and then began to add sodium hydroxide solution from the

buret. After adding 50 mL of NaOH solution, the sample in the flask still had not turned pink.

What error did the student make?

Answers

Answer 1

Answer:

The student shouldn't have added water to the acid.

Explanation:

The aim of titration is to standardize an unknown solution. Recall that a standard solution is one whose concentration is known.

After the acid has been prepared, it has a particular concentration. The student should't have diluted it further. The further dilution of a small volume of acid drastically reduces the concentration of the acid to such low value that the H^+ ions present are insufficient to react with the OH^- from base in order to turn the solution to pink.


Related Questions

What is a primary difference between bacteria that are in the
kingdom Archaea and other bacteria?

Answers

Answer:

Is there a way you can give a answer made for a 5th grade

Explanation:

If the shape of the moon appears to be increasing over time, what is
this called? *

A.waning
B.waxing
C.crescent
D.gibbous

Answers

Answer:

B

Explanation:

B hope that helps have a good one

In what areas of the country should this material be marked?

Answers

Answer:

Explanation: The goal of every country should be to produce more materials and goods

2. The diagram shows a Zn/MnO2-KOH alkaline dry cell.


In your response, do the following:
• Label all parts.
• Label the cathode and the anode, including the charges on each.
• Show the flow of electrons.
• Explain how the cell works. Include the oxidation and reduction half-reactions in your explanation.

Answers

Answer:

1. Graphite rod (cathode)

2. Positive terminal

3. Solid zinc layer (anode)

4. Paste (reduction takes place here)

5. Negative terminal

Explanation:

This was the only thing i could find on it. hope this helps.

Answer:

Explanation:

• Label all parts.

1. Cathode or Graphite Rod

2. Positive terminal  

3. Anode or Solid Zinc layer  

4. Electrolyte Paste (reduction takes place here)

5. Negative Terminal (maybe this could also be the Zinc casing)  

• Label the cathode and the anode, including the charges on each.

The anode is the zinc layer is negatively charged and the cathode is the graphite rod is positively charged.  

• Show the flow of electrons.

The zinc casing is oxidized and the electrons flow along the zinc layer, into the negative terminal, and then out the negative terminal. The electrons move from the wire to the graphite rod. Then from the rod the electrons move to the paste, then the past goes through reduction. The anode gets a negative charge as electrons are released, and the cathode gets a positive charge as the electrons, which are negatively charged, are consumed.

• Explain how the cell works. Include the oxidation and reduction half-reactions in your explanation.

Alkaline dry cells use spontaneous oxidation-reduction reactions to convert chemical energy to electrical energy. According to the lesson ‘’Half-reactions are combined in a small casing, but still separated into half-cells.’’

Why must an electron absorb a quantum of energy to move to a higher energy level?

Answers

Answer:

For an electron they start at the first level (n=1) In order to move up to the next level (n=2) the amount of quantom energy to move to this next level the energy must be perfect in order to move. If the quantom energy is to small the electron it doesn't try.

Finish the quote: “It’s not only about changing light bulbs, it’s about changing

Answers

Answer:

it's about changing attitudes and behavior.

What does an electromagnetic spectrum refer to?
O A. The energy of a photon emitted when an electron changes energy
levels
B. An angled piece of glass that splits up light into different
wavelengths
O C. A range of wavelengths of light that increases from one end to the
other
O D. The relationship between energy, wavelength, and frequency of
light
SUBMIS

Answers

Answer:

Explanation:

Option C is the correct answer

Among electromagnetic waves, UV rays are most dangerous because exposure to these radiation cause serious problems in living organism. Therefore, the correct option is option C.

What is electromagnetic wave?

Electromagnetic wave is a wave which contain two component one is electric component and other is magnetic component. The electric and magnetic component are perpendicular to each other. There are so many wave that comes under electromagnetic wave like infrared wave , radio wave.

There is a relation between energy of wave. frequency of wave, and wavelength of wave

Mathematically,

E=hc/λ

where,

E = energy of electromagnetic wave

h is planks constant having value 6.67×10⁻³⁴js

c is speed of light that is 3×10⁸m/s

λ is the wavelength of electromagnetic wave

An electromagnetic spectrum refer to a range of wavelengths of light that increases from one end to the other.

Therefore, the correct option is option C.

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what happens in a voltaic cell?
A.chemical energy is changed to a electrical energy
B. electrical energy is changed to chemical energy
C.electrical energy is changed to magnetic energy
D.magnetic energy is changes to electrical energy

Answers

Answer:

Hi ,

Answer:

A chemical energy is changed to a electrical energy

Which of the following diatomic gases has the shortest bond between its two atoms?
A. HI
B. O2
C. CI2
D. N2

Answers

The correct answer is D. N2
The answer is D. N2..

Im Stuck on this question for My Science homework​

Answers

Answer:

it's not clear

Explanation:

.

During a dilution, what happens to the concentration of a solution?
1
a.)The concentration increases
b.)The concentration decreases
c.) The concentration stays the same
d.)The concentration depends on the nature of the solute.

Answers

Answer:

B

Explanation:

Generally, when you dilute something, your goal is to thin your concentration. Even if you added a solute, if your goal is dilution, it will make the concentration decrease.

It’s B

Hope this helped!

Can you please help me to answer this?
I give you a brainlest! ​

Answers

9 is B
6 is A
i’m not sure about the rest

Calculate the number of moles in 8200 grams of iron
Can someone help me with this?

Answers

Answer:

150 moles (2 sig. figs.)

Explanation:

to convert from ...

grams to moles => divide by formula weight

moles to grams => multiply by formula weight

this problem:

Given mass of Iron (Fe) = 8200g

formula wt of Fe = 56g/mole

moles = mass/formula wt = 8200g / 56g/mol = 146.42857 moles (calculator) = 150 moles (2 sig. figs.)

The number of moles in 8200 grams of iron is 57.69 moles of Fe.

What is Mole concept ?

Mole is defined as the amount of the substance containing the same number of discrete entities (atoms, molecules, ions, etc) as there are atoms in a sample of pure 12C weighing exactly 12g.

The number of particles present in one mole of any substance  is Avogadro Number and is equals to 6.023 x 10²³ particles.

Given ;

Weight :  8200 grams of iron

To find ;

Mole (n) : ?

Formula used :

Mole (n) = given weight / atomic weight

             =  8200 / 56   (atomic weight of Fe = 56 gm)

             

             = 157.69 moles of Fe.

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Which of the following represent Dinitrogen tricarbide
1) NC
2) NC2
3) N2C2
4) N203​

Answers

Answer:

I think is nc2 that represents

Which statement is NOT true regarding Earth's past climate?
Group of answer choices

Earth was very warm 100 million years ago

Tropical forests and swamps covered much of Earth's surface many years ago

A shallow ocean covered much of North America 450 million years ago

Earth's climate has stayed the same throughout the past

Answers

Earth climate has stayed same thougout the past

What mass of NaOH is in 250 mL of a 3.0M NaOH solution​

Answers

Explanation:

Explanation: It's a 3.0 M solution so 1 litre of solution contains 3 moles of NaOH. 250 ml of solution therefore contains 0.25 x 3 = 0.75 moles of NaOH. The molar mass of NaOH is 39.9971 g/mol, so 250 ml of this solution contains 0.75 x 39.9971 = 29.99 g, or if you round it up 30.0 g.

30g of NaOH is in 250 mL of a 3.0M NaOH solution​.

What is Mole?

The mole is an amount unit similar to familiar units like pair, dozen, gross, etc. It provides a specific measure of the number of atoms or molecules in a bulk sample of matter.

A mole is defined as the amount of substance containing the same number of atoms, molecules, ions, etc. as the number of atoms in a sample of pure 12C weighing exactly 12 g.

Given,

Volume of NaOH = 250 ml

Concentration = 3M

number of moles = concentration × volume (L)

= 3 × 0.25

= 0.75 moles

mass = moles × molar mass

= 0.75 × 40

= 30 g

Therefore, 30g of NaOH is in 250 mL of a 3.0M NaOH solution​.

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please let me know if the answer is true or false. if false, please tell me what's false about it. the word that they are wondering if it needs to be changed is highlighted​

Answers

Answer:

false the answer is woody

Explanation:

those are the two types of stems

Set the Room temp. to -10.0 °C and observe. What is happening?

plzzz i need help on the ASAP no files/links

Answers

Answer:

its getting colder

Explanation:

WHAT IS THE PH OF LEMON JUICE IF IT HAS A HYDROGEN ION CONCENTRATION [AT]ON[H^ + ]=5.0*10^ -2 M.


Can somebody help me please !!!!!!

Answers

Answer:

ph=2

Explanation:


[tex]plz \: help \: me \: it \: is \: due \: 2moro[/tex]

Answers

Answer:

hi.

Explanation:

1. B

2. C

3. A

4. B

5.B

hope this helps

Science help this is my last question

Answers

Answer:

P waves travel faster than other waves

Explanation:

P waves travel fastest and are the first to arrive from the earthquake. In S or shear waves, rock oscillates perpendicular to the direction of wave propagation. In rock, S waves generally travel about 60% the speed of P waves, and the S wave always arrives after the P wave.

When you add the pH value of a solution to the pOH value of the same
solution together, at 25 degrees C, what should the combined value be?

ANSWER CHOICES
1. 7
2. 0, they should cancel each other out
3. 14
4. It’s indeterminate until you know the concentration values of hydrogen and hydroxide ions in solution

Answers

Answer:

3

Explanation:

pH+pOH=14

Calculate the heat absorbed, in kJ, when 2000. g of water is heated from 20.0 °C to 99.7 °C in an electric kettle

Answers

Answer:

666.93 kJ

Explanation:

Using the formula;

Q = m × c × ∆T

Where;

Q = amount of heat absorbed (Joules)

m = mass of substance (g)

c = specific heat capacity (4.184 J/g°C)

∆T = change in temperature (°C)

Based on the information provided in the question;

Q = ?

m = 2000g

∆T = 99.7 °C - 20 °C = 79.7 °C

c = 4.184 J/g°C

Using Q = m × c × ∆T

Q = 2000 × 4.184 × 79.7

Q = 666929.6 Joules

To calculate the amount of heat absorbed (Q) in kilojoules (kJ), we say;

1 joule = 0.001 kilojoule

666929.6 Joules = 666929.6 × 0.001

= 666.9296 KJ

Approximately, Q = 666.93 kJ.

2A + N2 -> 2AIN How many moles of aluminum nitride form when 5.00 g of aluminum reacts with excess nitrogen? K 0.0925 mol 0 0.185 mol Oleo mol z se mol​

Answers

Answer:

0.185 moles of AlN

Explanation:

The equation is:

2Al  +  N₂  →  2AlN

This reaction indicates that 2 mol of aluminum can react to 1 mol of nitrogen to produce 2 moles of aluminum nitride.

We convert the aluminum's mass to moles

5 g/ 26.98 g/mol = 0.185 moles.

2 moles of Al are needed to produce 2 moles of AlN

so, ratio is 1:1

In conclussion we say:

0.185 moles of Al, must produce 0.185 moles of AlN

The heart works directly with which
Liver
Lungs
Kidneys
Brain

Answers

Answer:

Lungs.

Explanation:

They bring the blood throughout the body, to help it function properly

Is NaCl solute or water ?

Answers

NaCl is a solute when dissolved in water

Nitrous acid is classified as an Arrhenius acid because HNO2 contains
1. OH-ions
2. 02-ions
3. NO2-ions
4. H+ ions

Answers

An Arrhenius acid is a molecule that when dissolved in water will donate an H+ in solution. ... Common examples of Arrhenius acids include: Hydrochloric Acid – HCl. Nitric Acid – HNO3.

4) H+ions is your answer , good morning , have a great day ahead.

2 moles of CaCl2 are dissolved in 0.6 liters of water. What is the molarity?

Answers

Answer:

b

Explanation:

2. How many moles of hydrogen are produced from the reaction of 3.86 moles of zinc with an excess of
hydrochloric acid?

Answers

Answer:

as per given balanced equation one mole Zn produces 1mole Hydrogen

when reacted with excess acid.

So 3 moles Zn will give 3moles Hydrogen

Explanation:

According to the balanced chemical equation, one mole of Zn produces one mole of hydrogen . Therefore, 3.86 moles of Zn metal will produce 3.86 moles of hydrogen gas.

What is mole ratio ?

Mole ratio refers to the ratio of the number of moles of one substance in a chemical reaction to the number of moles of another substance in the same reaction.

It is derived from the balanced chemical equation for the reaction, which indicates the relative amounts of each substance involved in the reaction.

Mole ratio is important in stoichiometry, which is the study of the quantitative relationships between reactants and products in a chemical reaction.

The given chemical reaction is written as follows:

Zn + 2 HCl ⇒ ZnCl₂ + H₂

According to the balanced chemical equation, one mole of Zn produces one mole of hydrogen . Therefore, 3.86 moles of Zn metal will produce 3.86 moles of hydrogen gas.

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In a solution, litmus is blue. The pH of the solution could be
1. 10
2. 2
3. 3
4. 4

Answers

Answer:

1. 10

Explanation

when litmus paper is blue that means the solution is basic and 10 on the pH scale is the most basic out of all your options

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