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3 years ago

Why do you think elements must be heated before they emit colored light?

1 answer:

4 0

The colored light emitted is energy and in order to emit energy the element should first obtain energy. The energy absorbed by the substance can be in the form of radiation, heat or electricity. Hope this answers the question. Have a nice day.

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Which separation method would be most successful in separating the components of a homogeneous mixture?

stiks02 [169]

I'm pretty sure the answer is B) Evaporation.

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3 years ago

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During which change of state would the volume of a substance increase the most?

Mademuasel [1]

Answer:

sublimation

Explanation:

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3 years ago

2 HI(g) ⇄ H2(g) + I2(g) Kc = 0.0156 at 400ºC 0.550 moles of HI are placed in a 2.00 L container and the system is allowed to rea

Alex_Xolod [135]

Answer: The concentration of hydrogen gas at equilibrium is 0.0275 M

Explanation:

Molarity is calculated by using the equation:

$\text{Molarity}=\frac{\text{Number of moles}}{\text{Volume of solution (in L)}}$

Moles of HI = 0.550 moles

Volume of container = 2.00 L

$\text{Initial concentration of HI}=\frac{0.550}{2}=0.275M$

For the given chemical equation:

$2HI(g)\rightleftharpoons H_2(g)+I_2(g)$

Initial: 0.275

At eqllm: 0.275-2x x x

The expression of $K_c$ for above equation follows:

$K_c=\frac{[H_2][I_2]}{[HI]^2}$

We are given:

$K_c=0.0156$

Putting values in above expression, we get:

$0.0156=\frac{x\times x}{(0.275-2x)^2}\\\\x=-0.0458,0.0275$

Neglecting the negative value of 'x' because concentration cannot be negative

So, equilibrium concentration of hydrogen gas = x = 0.0275 M

Hence, the concentration of hydrogen gas at equilibrium is 0.0275 M

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3 years ago

You have a 5-liter container with 1.30×10^24 molecules of ammonia gas (NH3) at STP.

givi [52]

Answer:answer is C

Explanation:

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3 years ago

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Explain how scientific observations led to the development of, and changes to, the periodic table.

Musya8 [376]

The following are scientific observations which led to development and changes of periodic table: Dmitri Mendeleev is the first periodic table organized 63 known element according to its properties, organized into rows and columns and inscribed name, mass and chemical properties on each element. Julius Lothar Meyer who independently worked in Germany with Ernest Rutherford. They experimented with 38 metals and found out that the positive charge of each element nucleus increased by one from element to element and organized the periodic table that tip to modern explanation of atomic number and the recognition of atomic number was the basis for organization of periodic table.

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3 years ago