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2 years ago

A 52.0 mL volume of 0.25 M HBr is titrated with 0.50 M KOH. Calculate the pH after addition of 26.0 mL of KOH at 25 ∘C.

1 answer:

7 0

The balanced equation for the above reaction is
HBr + KOH ---> KBr + H₂O
stoichiometry of HBr to KOH is 1:1
HBr is a strong acid and KOH is a strong base and they both completely dissociate.
The number of HBr moles present - 0.25 M / 1000 mL/L x 52.0 mL = 0.013 mol
The number of KOH moles added - 0.50 M / 1000 mL/L x 26.0 mL = 0.013 mol
the number of H⁺ ions = number of OH⁻ ions
therefore complete neutralisation occurs.
Therefore solution is neutral. At 25 °C, when the solution is neutral, pH = 7.
Then pH of solution is 7

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If 25.0 g of NH₃ and 45.0g of O₂ react in the following reaction, what is the mass in grams of NO that will be formed? 4 NH₃ (g)

Allisa [31]

Answer:

The correct answer would be : 33.8 g

Explanation:

Molar mass of ammonia,

Molar Mass = 1* Molar Mass(N) + 3* Molar Mass (H)

= 1*14.01 + 3*1.008 = 17.034 g/mol

mass(NH3)= 25.0 g (given)

number of mol of NH3,

n = mass of NH3/molar mass of NH3

=(25.0 g)/(17.034 g/mol)

= 1.468 mol

Now,

Molar mass of O2

= 32 g/mol

mass(O2)= 45.0 g

similar as ammonia

n (O2)=(45.0 g)/(32 g/mol)

= 1.406 mol

Balanced chemical equation is:

4 NH3 + 5 O2 ---> 4 NO + 6 H2O

1.83456 mol of O2 is required for 1.46765 mol of NH3

by the calculation we have only 1.40625 mol of O2

Thus, the limiting agent will be - O2

now the Molar mass of NO,

= 1*14.01 + 1*16.0

= 30.01 g/mol (similar formula used for NH3)

Balanced equation :

mol of NO formed = (4/5)* moles of O2

= (4/5)×1.40625 (from above calculation)

= 1.125 mol

mass of NO = number of moles × molar mass

= 1.125*30.01

= 33.8 g

Thus, the correct answer would be : 33.8 g

5 0

2 years ago

A laboratory instructor gives a sample of amino acid powder to each of four students, i, ii, iii, and iv, and they weigh the sam

Elena L [17]

Let us differentiate accuracy from precision. Accuracy is the nearness of the measured value to the true or exact value. On the other hand, precision is the nearness of the measured values between each other. So, for precision, select the student in which the measured values are very near to each other. That would be Student III. Now, for accuracy, let's find the average for each student.

Student I: (8.72g+8.74g+8.70g)/3 = 8.72 g
Student II: (8.56g+8.77g+8.83g)/3 = 8.72 g
Student III: (8.50g+8.48g+8.51g)/3 = 8.50 g
Student IV: (8.41g+8.72g+8.55g)/3 = 8.56 g

From the given results, the accurate one would be Students I and II. So, we make a compromise. Even though Student III is precise, it is not accurate. If you compare between Students I and II, the more precise data would be Student I. Therefore, the answer is Student I.

6 0

2 years ago

Read 2 more answers

Acetaminophen (pictured) is a popular nonaspirin, "over-the-counter" pain reliever. what is the mass % (calculate to 4 significa

77julia77 [94]

Acetaminophen as a chemical formula of C8H9NO2. The molar masses are:

C8H9NO2 = 151.163 g/mol

C = 12 g/mol

H = 1 g/mol

N = 14 g/mol

O = 16 g/mol

TO get the mass percent, simply multiply the molar mass of each elements with the number of the element divide by the molar mass of acetaminophen, that is:

%C = [(12 * 8) / 151.163] * 100% = 63.50%

%H = [(1 * 9) / 151.163] * 100% = 5.954%

%N = [(14 * 1) / 151.163] * 100% = 9.262%

%O = [(16 * 2) / 151.163] * 100% = 21.17%

8 0

2 years ago

A 0.200 M K 2SO 4 solution is produced by ________. dilution of 250.0 mL of 1.00 M K2SO4 to 1.00 L dissolving 43.6 g of K2SO4 in

Artist 52 [7]

A 0.200 M of K2SO4 solution is produced by diluting 20.0 mL of 5.00 M K2SO4 solution to 500.0 mL.

Explanation:

When dealing with dilution we will use the following equation:

M1 V1 = M2 V2

where,

M1 = initial concentration

V1 = initial volume

M2 = final concentration

V2 = final volume

By diluting 20.0 mL of 5.00 M K2SO4 solution to 500.0 mL, we get

M1 V1 = M2 V2

20.0 mL $\times$ 5.00 M = M2 $\times$ 500.0 mL

M2 = (20.0 mL $\times$ 5.00 M) / 500.0 mL

M2 = 0.200 M.

Hence A 0.200 M of K2SO4 solution is produced by diluting 20.0 mL of 5.00 M K2SO4 solution to 500.0 mL.

3 0

2 years ago

HELP HELP ASAP I WILL MARK BRAINLIEST

likoan [24]

Answer:

i cant read it

Explanation:

6 0

2 years ago