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3 years ago

When two substances are mixed together and a color change has occured, is it a chemical change?

1 answer:

5 0

There is a very likely chance that a color change indicated a chemical change. In order for an object to change color, a sample needs to change chemically so that it absorbs different light. I hope this helps. Let me know if anything is unclear or if you want further explanation.

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How many minutes will it take to plate out 2.19 g of chromium metal from a solution of Cr3+Cr3+ using a current of 55.2 amps in

Kamila [148]

Answer : The time it take to plate out will be, 3.69 minutes.

Explanation :

First we have to calculate the moles of Cr.

$\text{Moles of }Cr}=\frac{\text{Mass of Cr}}{\text{Molar mass of Cr}}$

Molar mass of Cr = 51.9 g/mol

$\text{Moles of }Cr}=\frac{2.19g}{51.9g/mol}=0.0423mol$

The cathode half-reaction is,

$Cr^{3+}+3e^-\rightarrow Cr$

From this we conclude that,

The number of electrons (n) in the reaction are 3.

The quantity of charge required for the reduction of 1 mole of $Cr^{3+}$ = $3\times F$

The quantity of charge required for the reduction of 0.0423 mole of $Cr^{3+}$ = $0.0423\times 3\times F=0.1269F=0.1269\times 96500C=12245.85C$

Now we have to calculate the time taken.

We know that,

$q=I\times t$

$t=\frac{q}{I}=\frac{12245.85C}{55.2A}=221.845s=3.69min$

Thus, the time it take to plate out will be, 3.69 minutes.

7 0

3 years ago

Matter with no definite shape or volume

MAVERICK [17]

Answer:

Gases have no definite shape or volume.

7 0

3 years ago

Which compounds in the form of solution conduct electricity

SIZIF [17.4K]

I believe that it is Ionic because it conducts electricity when dissolving in water

5 0

3 years ago

The most abundant trace gas in the atmosphere is _____. neon hydrogen argon helium

zhenek [66]

<em>Answer:</em>

Argon

<em>Explain:</em>

The most abundant gas in the atmosphere is Nitrogen (78.09%), The 2nd most abundant is oxygen (20.94%) and third one is argon (0.93%) and 4th one is CO2 (0.04%). While all others are in small amount like traces.

3 0

3 years ago

Read 2 more answers

Determine the number of moles of air present in 1.35 L at 750 torr and 17.0°C. Which equation should you use? P equals StartFrac

choli [55]

Answer:

0.056 moles air

Explanation:

P·V = n·R·T => n = P·V/R·T

P = 750 Torr = 750 mmHg = (750mm/760mm/atm) = 0.9868 Atm

V = 1.35 Liters

R = 0.08206 L·atm/mole·K

T = 17°C = (17 + 273) K = 290K

n = (0.9868atm)(1.35L)/(0.08206L·atm/mole·K)(290K) = 0.056 moles air

5 0

3 years ago

Read 2 more answers