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Marina86 [1]
2 years ago
12

Chromium (VI) forms two different oxyanions, the orange dichromate ion, Cr2o72-, And the yellow chromate ion, CrO4 2-. The equil

ibrium reaction between the ions is:
Cr2O7 2- (aq) + H2O(l)→ 2CrO4 2-(aq) + 2H(aq)
Explain
a) Why does the orange dichromate solution turn yellow when sodium hydroxide is added. Write the net ionic equation for this shift.
b) How will this system shift at equilibrium if the temperature is increased
Chemistry
1 answer:
MrRissso [65]2 years ago
4 0

Answer:

See explanation

Explanation:

Let us look at the reaction again;

Cr2O7 2- (aq) + H2O(l)⇄ 2CrO4 2-(aq) + 2H^+(aq)

When we add sodium hydroxide to the system as shown, the hydroxide ion removes the hydrogen ion thereby leaving a large concentration CrO4^2-(aq) in the system this causes the solution to turn green(equilibrium position shifts to the right).

The net ionic equation is;

OH^-(aq) + H^+(aq) ----> H2O(l)

The reaction;

OH^-(aq) + H^+(aq) ----> H2O(l) is exothermic hence, if the temperature of the system is increased, the equilibrium position will shift towards the left hand side and the solution turns orange.

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SNC2L Reflection Activities
slega [8]

The reflection from plane mirror is shown in the diagram.

<h3><u>Explanation</u>:</h3>

The mirror is a plane surface which can reflect light. The diagram attached shows the schematic representation of reflection that occurs in a plane mirror.

The laws of reflection states that the incident ray, reflected ray and the normal at the point of incidence lies at the same plane. Here we can also see that all are lying on a same plane.

The second law states that angle of incidence is equal to angle of reflection. Here we can also see that the i =r. It is applicable here too.

4 0
3 years ago
Match the following names of glassware with what you would use them for.
Valentin [98]

Answer:

A) Graduated pipette – Glassware used to accurately transfer small volumes.

B) Volumetric pipette – Glassware used to accurately transfer a small, single volume.

C) Beaker – Glassware best used when greater access to the contents is needed.

D) Buret – Glassware used to deliver a volume not known in advance.

E) Erlenmeyer flask – Glassware used to prevent splashing or evaporation.

F) Volumetric flask – Glassware used to make accurate solutions.

Explanation:

Graduated pipette – Glassware used to accurately transfer small volumes.

A graduated pipette is a pipette, which has a scale that shows its volume marked along the tube. It is used to transfer small volumes accurately.

Volumetric pipette – Glassware used to accurately transfer a small, single volume.

A volumetric pipette is a pipette, which has a ring like marking that is its calibrated volume. So it is used to transfer a single and small volume only. This pipette is used in volumetric analysis.

Beaker – Glassware best used when greater access to the contents is needed.

Beaker is the most widely used glassware in the laboratory. They are used to transfer large volume with less accuracy. They are of different sizes depends on the size of volumes ranging from 10 mL to 1000 mL.

Buret – Glassware used to deliver a volume not known in advance.

Buret is the most important glassware in the quantitative analysis. It has a glass tube with scale which measures the volume and a stopcock at one end from which the solvent is dispersed. It is used to measure the volume of the liquid during the titration in the quantitative analysis.

Erlenmeyer flask – Glassware used to prevent splashing or evaporation.

The most common names of Erlenmeyer flask are conical flask and titration flask. This flask has flat bottom, conical body and cylindrical neck which prevent splashing and evaporation. This flask is used in the titration process in the quantitative analysis. The solvent from the buret is delivered into the conical flask during the titration process.

Volumetric flask – Glassware used to make accurate solutions.

The volumetric flask is also an important glassware in the analytical laboratory. It is used to prepare standard solutions. It is a flask which has a ring like marking that is its calibrated volume. The mentioned volume of volumetric flask is calibrated to have accurate volume.

3 0
3 years ago
in an experiment 3.425g of lead oxide was reduced to form 3.105g of lead the empirical formula of the lead oxide is?​
Romashka-Z-Leto [24]

Answer:

Pb3O4

Explanation:

According to this question, 3.425g of lead oxide was reduced to form 3.105g of lead in an experiment. Since lead oxide contains both lead (Pb) and oxygen (O) element,

Mass of lead oxide = 3.425g

Mass of lead = 3.105g

Mass of oxygen = (3.425g - 3.105g) = 0.320g

Next, we convert each mass value to mole by dividing by respective molar mass

Pb = 3.105g ÷ 207.2 = 0.0149mol

O = 0.320g ÷ 16 = 0.02mol

Next, we divide each mole value by the smallest (0.0149)

Pb = 0.0149mol ÷ 0.0149mol = 1

O = 0.02mol ÷ 0.0149mol = 1.342

Multiply each ratio value by 3 to get:

Pb = 1 × 3 = 3

O = 1.342 × 3 = 4.026

The whole number ratio, approximately, of Pb and O is 3:4, hence, their empirical formula is Pb3O4.

4 0
3 years ago
How many grams of Fe2+ are there in 0.003109 moles of Fe2+?
Sergio [31]

Answer: 0.174 g

Explanation:

First of all understand that charge on an atom like here 2+ will not vary molar mass. because ions are formed by loss or gain of electrons and electrons do not contribute to the mass of an atom or ion. so losing or gaining electron doesnt create any difference.

molar mass of Fe, i.e. mass of 1 mole of Fe is 56 g. So, mass of 1 mole of Fe2+ will also be 56 g.

given is 0.003109 moles of Fe2+,

Use maths,

1 mole of Fe2+ weighs 56 g

So, 0.003109 moles will weigh = (56 g / 1 mol ) x 0.003109 = 0.174 g.

7 0
3 years ago
Which of the following best describes what happens when molecular compounds melt? A.) Molecules separate into their component at
Semenov [28]
I think the correct answer from the choices listed above is option D. When a molecular compound melts, they undergo the process of phase change from solid to liquid therefore m<span>olecules arranged in a regular pattern change to an irregular pattern. Hope this answers the question.</span>
3 0
3 years ago
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