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3 years ago

Why are the discrete lines observed and not a continuous spectrum?

1 answer:

6 0

Atoms of individual elements emit light at only specific wavelengths, producing a line spectrum rather than the continuous spectrum of all wavelengths produced by a hot object.

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Which of the following reactions have a positive ΔSrxn? Check all that apply.

PolarNik [594]

Answer:

The reactions that have a positive ΔS rxn are the first and the fourth choices:

2A(g) + B(s) → 3C(g)

2A(g) + 2B(g) → 5C(g)

Explanation:

ΔS rxn is the change of entropy of the chemical reaction.

ΔS rxn = S after reaction - S before reaction.

Therefore, a positive ΔS rxn means that the entropy after the reaction is greater than the entropy before the reaction.

You may use some assumptions to predict whether a reaction will lead an increase or decrease of the entropy.

First, assume that all the non-shown conditions, such as temperature and pressure, are constant.

Under that assumption, and from the meaning of entropy as a measure of the disorder or randomness of a system you can predict the sign of the change of entropy.

2A(g) + B(s) → 3C(g)

1) The solid compounds, B(s) in this case, are very ordered and so they have low entropy.

2) Gas molecules are highly disordered (scattered), and the greater the number of molecules of the gas the larger the entropy, S).

Hence, since the product side shows 3 gas molecules and the reactant side shows 2 gas molecules and 1 solid molecule, you predict that the products have a larger entropy than the reactants, meaning an increase in entropy: ΔS rxn is positive.

2A(g) + B(g) → C(g)

Using the same reasoning, 3 gas molecules in the reactant side have more entropy than 1 molecule in the product side, and so the reaction leads to a decrease in the entropy: ΔS rxn is negative

A(g) + B(g) → C(g)

Again, 2 gas molecules in the reactant side have more entropy than 1 molecule in the product side, and so the reaction leads to a decrease in the entropy: ΔS rxn is negative

2A(g) + 2B(g) → 5C(g)

With the same reasoing, 5 molecules in the product side, lets you predict that will have more entropy than 4 molecules in the reactant side, and, the entropy will increase: ΔS rxn is positive.

6 0

3 years ago

4 Weathering Assessment

alexira [117]

Answer:

This is an example of chemical change because the Kool aid dissolved and turned the water red

6 0

2 years ago

¿como afecta la temperatura el volumen de un gas?

Oxana [17]

Lo afect porque cuando la temperature aumenta, el volumen aumentará, luego, cuando we mantiene la presión, es constante. Calentar el gas aumenta la emergía cinética we law partículas, lo que have que el gas se expanda.

Espero que esto ayude :)

8 0

3 years ago

Chlorine is the most widely used disinfectant for killing pathogens during water treatment. Determine the kilograms of chlorine

makkiz [27]

Explanation:

The given data is as follows.

Flow of chlorine (Q) = $10,000 m^{3}/day$

Amount of liter present per day is as follows.

$10,000 \times 10^{3} l/day$

It is given that dosage of chlorine will be as follows.

10 mg/l = $10 \times 10^{-6}$ kg/l

Therefore, total chlorine requirement is as follows.

Total chlorine requirement = $(10,000 \times 10^{3}) \times (10 \times 10^{-6})$ kg/day

= 100 kg/day

Thus, we can conclude that the kilograms of chlorine used daily at the given water treatment plant is 100 kg/day.

4 0

3 years ago

During heat transfer, thermal energy always moves in the same direction: A. COLDHOT B. HOT COLD C. No movement D. HOTHOT

drek231 [11]

Answer: Option (B) is the correct answer.

Explanation:

Thermal energy is defined as the energy present within the molecules of a substance.

Also, when two objects that have different temperature and they are in contact with each other then heat will always flow from hot object to cold object.

For example, if a metal spoon is placed in a hot cup of coffee then heat will flow from hot coffee to the metal spoon.

Therefore, we can conclude that during heat transfer, thermal energy always moves in the same direction: HOT COLD.

6 0

3 years ago

Why are the discrete lines observed and not a continuous spectrum?​

Why are the discrete lines observed and not a continuous spectrum?