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3 years ago

Suppose you wanted to monitor a pH change between 8.7 and 7.7. Which indicator would be most appropriate

Chemistry

1 answer:

mariarad [96]3 years ago

5 0

Answer:

Phenol red /

Thymol blue

Explanation:

pH indicator referred to halochromic chemical compound which is added in small amounts to a solution for the determination of pH visually.

An indicator can be described as a chemical detector for both hydronium and hydrogen ions as far as Arrhenius model is concerned, an indicator are usually weak acids or bases, and when they are which dissolved in water , there would be a dissociation process and ions is formed.

There are different types of indicator used in the laboratory depending on the pH values of the solution examples are thymol blue, bromothymol blue, thymol blue, phenolphthalein and methyl red

Thymol blue is an indicator that transit between red to yellow when the pH is between the range of 1.2–2.8 and also transit from from yellow to blue when the pH 8.0–9.6. It an indicator that usually have brownish-green or reddish-brown crystalline powder

Phenol red is pH indicator which is yellow in colour when it is below 6.8 pH and has a very bright pink colour when used with pH above 8.2

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2 years ago

Condensation point and freezing point of argon in KELVIN.

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Answer:

Condensation: 423.3 K

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3 years ago

What is the partial pressure of argon, par, in the flask? express your answer to three significant figures and include the appro

monitta

Given which are missing in your question:
the flask is filled with 1.45 g of argon at 25 C°
So according to this formula (Partial pressure):
PV= nRT
first, we need n, and we can get by substitution by:
n = 1.45/mass weight of argon
= 1.45 / 39.948 = 0.0363 mol of Ar
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and V = 1 L
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3 0

3 years ago

1) What mass of Na2CO3 is required to make 50cc of its seminormal solution?

love history [14]

Answer:

$m=1.325gNa_2CO_3$

Explanation:

Hello,

In this case, by considering the given seminormal solution, we infer it is a 0.5-N solution which means that we can obtain the equivalent grams as shown below for the 55 cc (0.055 L) volume:

$eq-g=0.5eq-g/L*0.050L=0.025eq-g$

Next, since sodium carbonate has two sodium ions with a +1 oxidation state each, we can obtain the moles:

$mol=0.025eq-gNa_2CO_3*\frac{1molNa_2CO_3}{2eq-gNa_2CO_3}\\ \\mol=0.0125molNa_2CO_3$

Finally, the mass is computed by using its molar mass (106 g/mol)

$m=0.0125molNa_2CO_3*\frac{106gNa_2CO_3}{1molNa_2CO_3} \\\\m=1.325gNa_2CO_3$

Regards.

7 0

3 years ago