Category: Chemistry-11
Flame lab
Application questions:
What particles are found in the chemicals that may be responsible for the production of colored light?
The photons. When a quantum leap happens the photons are responsible for emiting the light.
Why do different chemicals emit different colors of light?
They have different photons which have different wave lengths
Why do you think the chemicals have to be heated in the flame first before the colored light is emitted?
Because to make a quantum leap you need a source of energy which the flame provides.
Coloured light is emitted constantly around us during our everyday experiences. List 5 examples of coloured light emissions you have seen in the last week.
LED light, sun, fluorescent, fire, traffic lights
Write out the electronic configuration for each of the metallic ions to be investigated.
Copper ion: 1s2 2s2 2p6 3s2 3p6 3d9
Strontium ion: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
Lithium ion: 1s2
Potassium ion: 1s2 2s2 2p6 3s2 3p6
Calcium ion: 1s2 2s2 2p6 3s2 3p6
Zinc ion: 1s2 2s2 2p6 3s2 3p6 3d10
Why are all the metallic ions paired with nitrate?
All the ions are paired with nitrate due to nitrate being soluble in water. Since all metals except for a select few are soluble, if you didn’t have the nitrates the metals would not be able to create the liquid spray we used.
What wavelengths correspond to the visible spectrum? Which colour has the shortest wavelength? The longest? What unit are wavelengths measured in?
The wavelengths from 400nm-700nm correspond to the visible spectrum. Violet is the shortest wavelength and red has the longest. Wavelengths are measured in nanometers to represent how long the actual wavelength is.
Hydrate lab
In this lab we calculated the percent,(by weighing the hydrates and heating them to eliminate the water) of water in two hydrated salts, and how to figure out the formula of two hydrated salts. We were given two unknown hydrates and the molar mass of the anhydrous salts. We then heated the anhyrdrous salt with the hydrate to burn off the water. After 5 minutes we took them of the flame and let them cool for another 5 minutes. After we re measured their weight, We repeated this process for the second hydrate.
This is what our station looked like before we started the heating process.
Weighing hydrate A before heating it
Weighing Hydrate A with the crucible after the first 5 minute heating process. It looked like a white powder.
Weighing Hydrate A after the second heating process. It looked the same but dryer and had brown spots on the powder.
FORMULA OF A HYDRATE
Data:
HYDRATE: A HYDRATE: D
Molar mass of anhydrous salt: 142.0 g/mol 161.5 g/mol
Mass of crucible & lid: 35.27 g 32.92 g
Mass of hydrate: 2.16 g 2.36g
Mass of crucible, lid
& contents (1st heating) 36.06 g 34.26 g
Mass of crucible, lid
& contents (2nd heating) 36.06 g 34.29 g
Calculations & Conclusion:
1. Use the given molar masses of the anhydrous salts to determine the moles of anhydrous salt present after heating each of the hydrates.
A- (35.27 + 2.16) – 36.06 = 1.37 / 142.0 = 0.00960 mol of salt
D- ( 32.92 + 2.36) – 34.29 = 0.99 / 161.5 = 0.00610 mol of salt
2. Determine the mass and moles of water lost for each hydrate.
A- ( 2.16 – 1.37) = 0.79g of H2O / 18g/mol = 0.0439mol of H2O
D- (2.36 – 0.99) = 1.37g of H2O / 18g/mol = 0.0761mol of H2O
3. Determine the formula of each hydrate in the form of X. __H2O (X = unknown salt) by comparing the ratio of moles of H2O: moles anhydrous salt.
A- 0.0439 / 0.0096 = 4.57 -> 5H2O per salt
D- 0.0761 / 0.00613 = 12.41 -> 12H2O per salt
4. Determine the % composition (mass) of water in each hydrated salt.
A- 0.79/ 2.16 = 36.6% of H2O
D- 0.0761/ 0.00613 = 58.1% of H2O
Types of reactions
1. We lit magnesium on fire which caused a bright uv light and the the magnesium turned into a white powder.
2. When we turned the torch on the flame was green and it gradually changed to blue.
3.When we added a potassium iodide crystal to the hydrogen peroxide it began to turn orange and bubble, it then expanded out of the graduated cylinder and began to steam a small amount and was very hot and smelly.
4. When we put the copper into the silver nitrate it immediately grew black spots on it and the longer we left it, it grew into a mold like substance.
5. When we added a drop of the lead (||) nitrate to the potassium iodide it instantly turned yellow.
6. When we mixed the sodium hydroxide (base) and the sulphuric acid (acid) together they made an acid.
