Why does a salt compound give off light (or a colored flame) when burned? 4. did lithium chloride and sodium chloride give off similar colors? why or why not? 5. explain what you think causes different compounds to give off different flame colors. 6. using your results, identify which substances you would put in a firework to delight a crowd of spectators?

The salt compounds give off light due to their emission spectrum.

(4) , lithium chloride and sodium chloride do not give off similar colors because of the difference in their emission spectrum.

(5) Flame colors are characteristics of between the two levels, which is different for different elements.

(6) can be put in a firework.

Further explanation:

Electronic transition:

An electronic transition is a process that occurs when an electron undergoes emission or absorption from one energy level to another energy level.

When an electron undergoes a transition from lower energy level to the higher energy level then it requires energy to complete the process. This transition is an absorption process.

When an electron undergoes a transition from higher energy level to lower energy level then it emits energy to complete the process. This transition is an emission process.

The formula to calculate the difference between two energy levels of an atom is,

Where,

is the energy difference between two energy levels.

is Rydberg constant.

is the initial energy level of transition.

is the final energy level of transition.

The salt compound gives off the light because its electrons absorb energy and get excited to some higher energy level. But when it returns to the lower level, it emits energy in the form of light, resulting in emission spectrum.

(4) No, lithium chloride and sodium chloride do not give off similar colors. This is because both these compounds have different allowed energy levels for their respective electrons. Lithium ion shows a red emission spectrum while sodium ion shows yellow emission spectrum.

(5) Different elements have different allowed energy levels for electrons. When an atom is heated, it absorbs energy and reaches some higher energy level. When an electron jumps from higher energy level to lower energy level, it emits energy in form of light. The wavelength of light depends on the energy difference between the two levels, which is different for different elements, and therefore different elements show different flame colors.

(6) Salts of alkali and alkaline earth metals can be used in fireworks as these are highly electropositive metals and give off electrons so easily and bright colored flames are produced. For example, barium chloride gives off the green flame when burned.

Learn more:

1. Component of John Dalton’s atomic theory:

2. Basis of investigation for the scientists:

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Atomic structure

Keywords: electronic transition, barium chloride, colored flames, alkali, alkaline earth metals, electropositive, emission, absorption, electrons, allowed energy levels, higher level, lower level.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.