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4 years ago

Which of the following aqueous solutions are good buffer systems?

1 answer:

5 0

Buffer is composed of weak acid and its conjugate base or weak base and it is conjugate acid. so The correct answer is:
0.21 M hydrofluoric acid + 0.20 M potassium Fluoride
due to the first choice contain NaOH which is strong base not weak
second choice both salts no acid or base
Third choice contain HNO₃ which is considered as strong acid
Fourth choice contain ammonia but without its conjugate acid like (NH₄Cl for example) instead it has different salt
Fifth Choice contain HF which is weak acid and KF which is its conjugate base so this is the correct one

You might be interested in

5. A gas occupies 2000. Lat 100.0 K and exerts a pressure of 100.0 kPa. What volume will

Anna [14]

Answer:

4000 L

Explanation:

Step 1:

Data obtained from the question. This include the following:

Initial volume (V1) = 2000 L.

Initial temperature (T1) = 100 K.

Initial pressure (P1) = 100 kPa.

Final temperature (T2) = 400 K.

Final pressure (P2) = 200 kPa.

Final volume (V2) =..?

Step 2:

Determination of the new volume of the gas.

The new volume of the gas can be obtained by using the general gas equation as follow:

P1V1/T1 = P2V2/T2

100 x 2000/100 = 200 x V2/400

Cross multiply to express in linear form.

100 x 200 x V2 = 100 x 2000 x 400

Divide both side by 100 x 200

V2 = (100 x 2000 x 400)/(100 x 200)

V2 = 4000 L

Therefore, the new volume of the gas is 4000 L

5 0

3 years ago

Which statements describe the relationship between the area and the biodiversty of the ecosystem check all that apply

wel

Answer:

I don't know what the choices are, but take a picture of the choices

4 0

3 years ago

Write a balenced chemical equation for the reaction: include abbreviation for the physical states-

WITCHER [35]

Answer:

MgBr(aq) + (NH4)3PO4(aq) -------> NH4Br(aq) + Mg3(PO4)2(s)

Explanation:

4 0

3 years ago

If 16.4 grams of copper (II) bromide react with 22.7 grams of sodium chloride, how many grams of sodium bromide are formed?

fomenos

The amount of sodium bromide that would be formed from the reaction will be 7.5524 grams

<h3>Stoichiometric calculation</h3>

Looking at the equation of the reaction:

$CuBr_2 + 2NaCl --- > CuCl_2 + 2NaBr$

The mole ratio of CuBr2 and NaCl is 1:2.

Mole of 16.4 grams of CuBr2 = 16.4/223.37

= 0.0734 moles

Mole of 22.7 grams of NaCl = 22.7/58.44

= 0.3884 moles

Equivalent mole of NaCl = 0.1468 moles

Thus, NaCl is in excess while CuBr2 is limiting.

Mole ratio of CuBr2 and NaBr = 1:1

Mass of 0.0734 mole NaBr = 0.0734 x 102.894

= 7.5524 grams

More on stoichiometric calculation can be found here: brainly.com/question/8062886

4 0

3 years ago

I'm stuck on this assignment, +20 PTS and BRAINLIEST for step by step:

dolphi86 [110]

Answer:

2. 2.74 L

3. 488 K

4. 7.47 L

5. 38.6 L

6. 2.85 mol

7. 319 K

8. 3.43 kPa

Explanation:

Generally speaking, you want to convert units to SI units, but in this case, we are working with ratios. This makes up for using the units that wouldn't appropriate elsewhere.

2. Use the equation P₁V₁ = P₂V₂. Solve for V₂.

(3.05 L)(870 kPa) = (969 kPa)(V₂)

V₂ = 2.74 L.

3. Use the equation V₁/T₁ = V₂/T₂. Solve for T₂.

(3.32 L)/(360 K) = (4.50 L)/(T₂)

T₂ = 488 K.

4. Do the same as above, but for V₂.

(5.10 L)/(-56°C) = V₂/(-82°C)

V₂ = 7.47 L

5. Use the equation V₁/n₁ = V₂/n₂. Solve for V₂.

(37.2 L)/(0.750 mol) = (V₂)/(0.778 mol)

V₂ = 38.6 L

6. Do the same as above, but for n₂.

(86.0 L)/(2.65 mol) = (92.5 L)(n₂)

n₂ = 2.85 mol

7. Use the equation P₁/T₁ = P₂/T₂. Solve for T₂.

(3.00 atm)/(390 K) = (2.45 atm)/(T₂)

T₂ = 319 K

8. Do the same as above, but for P₂.

In this specific case, however you will need to convert units. Since both temperatures don't have the same sign, the ratio won't come out right. Convert to Kelvin. Add 273.15 to the temperature in Celsius to convert to Kelvin -12.3°C = 260.85 K 25°C = 298.15 K.

(3.00 kPa)/(260.85 K) = P₂/(298.15 K)

P₂ = 3.43 kPa

There is a lot in here... If you are confused about something, let me know!

6 0

3 years ago