Chem Lab quiz 10/15/19

This experiment mostly demonstrates qualitative data. What is qualitative data and quantitative data? When did you observe quantitative and qualitative in this experiment?

Qualitative data = categorical, data that can't be measured with numbers Quantitative data = relating to, measuring, or measured by the quantity of something rather than its quality. Qualitative data = color emitted Quantitative data = wavelength(nm)

A glass rod is heated in a burner flame and gave off a bright yellow flame. What metal ion predominates in the glass rod?

Sodium

How could this test be used for application in fireworks?

The different types of metals can be used to make different colors of fireworks. Used to identify what different elements make up different colored fireworks to know how to build certain color fireworks.

You observed many different lines for each element. What might cause the different light emitted?

3 ways to excite electrons: Heat Light Electricity E = hr C = r*wavelength Wavelength corresponds to color of light The electrons get excited and absorb energy and go to a new wavelength then come back down and emit different energies correlating to different frequencies which then correlates to different lights.

Explain what you think caused different lines for different elements.

Because the elements have different numbers of electrons and protons. With more protons compared to electrons, it creates less distance between electrons and protons which changes the wavelength and frequency when the electrons are excited by heat, electricity or light. Therefore, this creates the different lines for different elements.

What evidence is there to support that the characteristic color of each compound is due to the metal in each case, and not the nonmetal?

Because there is a constant nonmetal(chloride) in all of them, and if it was the nonmetal then it would all be the same color. However, the only variable is the metal in all of them so that is what causes the characteristic color of each compound.

Why don't you see light emitted when water is heated in a flame?

Because there is no metal in water and that is what creates the visible light. What is fire = excited electrons of CO2 and oxygen and air that gives off light.

The alkali metals cesium(Cs) and rubidium(Rb) were discovered based on their characteristic flame colors. Cesium is named after the sky and rubidium after the gem color. What colors of light do you think these metals give off when heated in a flame?

Cesium =light blue, rubidium = red

A spec-20 analysis machine uses light to identify metal atoms that are present in compounds. Based on this experiment, identify what processes the spec-20 machine must be able to do in order to identify unknown elements automatically.

Excites the electrons with light or electricity and they come back down and emit different wavelengths. The wavelengths go through a prism and then hits a screen that calculates the wavelengths. Then you compare the wavelengths to the elements.

Why do you think the chemicals have to be heated in the flame first before the colored light is emitted?

Heat is what excites the electrons to emit the different lights.

How could this test be used for astronomy?

You can look through a spectrometer at a star at the colors and wavelengths noted on the spectrometer and match those colors and wavelengths to the ones that are present in the make up of elements to determine what elements each star is made of.