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slega [8]
3 years ago
8

When phenolphthalein indicator is added to a colorless solution with a pH of 10, a student observes and concludes that the teste

d solution
1
remains colorless and is basic
2.
remains colorless and is acidic
3.
turns pink and is basic
4.
turns pink and is acidic
Chemistry
1 answer:
madam [21]3 years ago
4 0

Answer:

3.  turns pink and is basic

Explanation:

Phenolphthalein is a pH indicator that remains colorless in acidic solutions, but in basic solutions it turns pink at a pH equal to 10.

Phenolphthalein is a weak acid that loses H+ cations in solution. The phenolphthalein molecule is colorless, while the phenolphthalein-derived anion is pink. When a base is added, phenolphthalein loses H+, forming the anion and causing it to turn pink. The color change cannot be explained only on the basis of deprotonation, a structural change occurs with the appearance of a ketoenolic tautomerism.

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What mass of KNO3 would be needed to produce 18.4 liters of oxygen gas, measured at 1.50 x 10^3 kPa and 15 degrees Celsius?
Brut [27]

Answer:-

2328.454 grams

Explanation:-

Volume V = 18.4 litres

Temperature T = 15 C + 273 = 288 K

Pressure P = 1.5 x 10^ 3 KPa

We know universal Gas constant R = 8.314 L KPa K-1 mol-1

Using the relation PV = nRT

Number of moles of oxygen gas n = PV / RT

Plugging in the values

n = (1.5 x 10^3 KPa ) x ( 18.4 litres ) / ( 8.314 L KPa K-1 mol-1 x 288 K)

n = 11.527 mol

Now the balanced chemical equation for this reaction is

2KNO3 --> 2KNO2 + O2

From the equation we can see that

1 mol of O2 is produced from 2 mol of KNO3.

∴ 11.527 mol of O2 is produced from 2 x 11.527 mol of KNO3.

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7 0
3 years ago
How many simple distillation columns are required to purify a stream containing five components into five 'pure"products? Sketch
katen-ka-za [31]

Answer: one simple distillation column is required to separate the stream into five pure products. With four different flat bottom flask, for collection of the distilled products

Explanation: simple distillation works with the difference in boiling points of the liquid to be separated. For the separation of five different constituent to be possible, we have to know the boiling points of the constituents.

For your understanding, let's define constituents in the liquid to be A, B, C, D, E. And the boiling points increases respectively. Start by heating the liquid to the boiling point of A to extract A. After a while check if the constituents A is still dropping in the flat bottom flask, if it has stopped dropping, it simply means that we have extracted all A constituents in the liquid, label the Flask A. Get another flask to extract constituent B.

Heat the mixture to the boiling point of B, after a while check if constituent B is still dropping in the flat bottom flask, if it has stopped dropping,it means that we have extracted all B constituent in the liquid, label the Flask B. Get another flask for C.

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SEE PICTURE TO UNDERSTAND WHAT A SIMPLE DISTILLATION LOOKS LIKE

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3 years ago
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Dominik [7]

Hello. This question is incomplete. The full question is:

"Consider the following reaction.  2NO(g) + 2H2(g) → N2(g) + 2H2O(g)

A proposed reaction mechanism is:  NO(g) + NO(g) N2O2(g) fast  N2O2(g) + H2(g) → N2O(g) + H2O(g) slow  N2O(g) + H2(g) → N2(g) + H2O(g) fast

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Explanation:

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These mechanisms are directly related to chemical kinetics and allow changes in reaction rates to be observed in advance.

Reaction rate, on the other hand, refers to the speed at which chemical reactions occur.

Based on this, we can observe through the reaction mechanism shown in the question above, that the action "k [H2] [NO] 2" would have no changes in the reaction rate.

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3 years ago
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