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3 years ago

5

Why does an ultraviolet light cause paint to fade

1 answer:

GarryVolchara [31]3 years ago

7 0

Answer:

There are light absorbing color bodies called chromophores that are present in dyes. Ultraviolet rays are one of the causes of fading because they can break down chemical bonds and fade the color in objects.

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Would a thermos without a lid with water in it be an open or closed system? I'm so confused... also please explain your answer,

Dmitriy789 [7]

Answer:

. A closed system allows only energy transfer but no transfer of mass. Example: a cup of coffee with a lid on it, or a simple water bottle. ... In reality, a perfectly isolated system does not exist, for instance hot water in a thermos flask cannot remain hot forever.

8 0

3 years ago

Consider the following reaction: CH3OH(g)⇌CO(g)+2H2(g) Part A Calculate ΔG for this reaction at 25 ∘C under the following condit

kati45 [8]

<u>Answer:</u> The $\Delta G$ of the reaction at given temperature is -12.964 kJ/mol.

<u>Explanation:</u>

For the given chemical reaction:

$CH_3OH(g)\rightleftharpoons CO(g)+2H_2(g)$

The expression of $K_p$ for the given reaction:

$K_p=\frac{(p_{CO})\times (p_{H_2}^2)}{p_{CH_3OH}}$

We are given:

$p_{CO}=0.140atm\\p_{H_2}=0.180atm\\p_{CH_3OH}=0.850atm$

Putting values in above equation, we get:

$K_p=\frac{(0.140)\times (0.180)^2}{0.850}\\\\K_p=5.34\times 10^{-3}$

To calculate the Gibbs free energy of the reaction, we use the equation:

$\Delta G=\Delta G^o+RT\ln K_p$

where,

$\Delta G$ = Gibbs' free energy of the reaction = ?

$\Delta G^o$ = Standard gibbs' free energy change of the reaction = 0 J (at equilibrium)

R = Gas constant = $8.314J/K mol$

T = Temperature = $25^oC=[25+273]K=298K$

$K_p$ = equilibrium constant in terms of partial pressure = $5.34\times 10^{-3}$

Putting values in above equation, we get:

$\Delta G=0+(8.314J/K.mol\times 298K\times \ln(5.34\times 10^{-3}))\\\\\Delta G=-12963.96J/mol=-12.964kJ/mol$

Hence, the $\Delta G$ of the reaction at given temperature is -12.964 kJ/mol.

5 0

3 years ago

What property of these items do cm or mm measure: length, volume, mass or temperature?

UNO [17]

Answer:

length

Explanation:

cm measures length. Think of a ruler.

7 0

3 years ago

Four grams of magnesium react with an excess of dilute hydrochloric acid. Calculate the volume in liters of hydrogen gas collect

Helga [31]

Sorry I am confuse 3

5 0

3 years ago

What are complementary bases?

Radda [10]

Answer:

Two Sections that contain nitrogen of a nucleotide that bond together to connect strands of DNA or RNA.

Explanation:

3 0

3 years ago