Unit 1 Wrap Up

It was great to meet so many of your families at Open House! We finished Unit 1 - Atomic Structure last week. In periods 1 and 3 we played Chemistry Baseball to review our Unit 1 Objectives!

Remember that test retakes can be done in room 120 - you must show your GOLD ticket to retake.

Speaking of gold, here's are some shots of our "marbles" lab where we modeled Rutherford's Gold-Foil Experiment to estimate the diameter of a marble by the percentage of "hits" and "misses"!

Converting Copper...and Back Again!

In Honors Chemistry we explored the idea of Conservation of Matter - the idea that atoms cannot be created or destroyed in chemical reactions.

We first heated pure copper to convert if to copper(II) oxide. Many students were surprised that the mass increased after heating!

Then we reacted the copper(II) oxide with dilute hydrochloric acid to dissolve the copper +2 ions in solution.

Finally, we reacted the blue aqueous copper +2 solution with either zinc or aluminum to retrieve the copper again!

(thanks to BigScienceNotebook for some of the images!)

Welcome Back! Introducing the Black Box...

Welcome back to school, chemists!

I know I had a great summer working on some curriculum projects and spending time with my family.

In chemistry we are diving right in to scientific experimentation and the nature of the atom. We did a class activity where we explored what was inside of a "Black Box" through indirect experimentation. We did this to model the process that scientists go through when trying to discover the nature of things that are too small to see, touch, and otherwise observe directly.

In period 3 we first tried pouring 99 mL of water into the Black Box and were very surprised when only about 85 mL of a bluish-green, odorless liquid came out!

We then tried adding 99 mL of vinegar into the Black Box and were even more surprised when 88 mL of a brighter green, vinegar-smelling liquid came out!

What do YOU think is inside the Black Box? Below are some of our drawings of what we think might be inside.

Equilibrium - "Hungry Hungry Hippos" style

Today we did an activity where we modeled a reversible reaction achieving equilibrium in a "closed" system. One person was the agitator representing the kinetic energy of the molecules, one person represented the "forward reaction" by putting together the beads into pairs, while another person represented the "reverse reaction" by trying to take apart the pairs at the same time! We had a great and noisy time while experiencing equilibrium at the particle level. This was a truly hands-on experience!

More Supersaturated Solutions - Per 8!

I just had to include these great pictures from period 8's supersaturated solutions lab; you can really see the crystals!

Temperature Dependent Solubility of KNO3

Today we generated a solubility curve for KNO3.

SUPERsaturated solutions!

We have been learning about the concept of solubility and different types of solutions based on the amount of solute dissolved.

Today we did a lab experiment where we created unsaturated, saturated, and supersaturated solutions!

The solute we used was sodium thiosulfate.

We first dissolved a small amount of solute in water to create an unsaturated solution, which looks somewhat clear with no undissolved solid.

Then we added more solute until the solution was saturated, as evidenced by the undissolved crystals on the bottom of the test tube.

Then we heated the mixture as the solubility of the sodium thiosulfate increases as the temperature increases.

 Finally, we cooled the test tube to reduce the solubility, and "disturbed" the solution by adding a single additional crystal of the solute. The excess solute crystallized out in a dramatic fashion!

Factors Affecting Rates of Dissolution

Today we performed a small inquiry experiment to determine which factors affect the rates of dissolution. Students had to design their own procedure to test how surface area, solvent temperature, and stirring affected how much sugar dissolved in water.

The students did a great job with setting up their experimental constants such as the amount of water, amount of sugar, and method of stirring.

Be sure to ask the chemists what they discovered!

Egg in a Flask

In 8th period we put a boiled egg in a flask!

Can you explain how we got the egg into the flask?

Can you explain how we got the egg out again?

Ask your chemist!

(Thanks to this web page for the great sequential picture!)

Marshmallows Again: Pressure-Volume

Today we explored the inverse relationship between Pressure and Volume of a gas using plastic syringes. We experienced this relationship by feeling the "push" and "pull" against the gas molecules both inside the syringe and outside, saw this visually using marshmallows inside the syringe, and also used the Logger Pro software and Vernier Gas Pressure sensors to graph this relationship.

Deriving Absolute Zero: Pressure and Temperature

Today we did a simple activity where we measured the pressure of a gas in a sealed steel sphere (try saying that three times fast!) at three different temperatures.

We graphed our data points and then extrapolated a best-fit line to estimate the x-intercept. We discussed that this was the point of ABSOLUTE ZERO, -273 degrees Celsius, the point of zero kinetic energy!

We were amazed that gas particles behave in a way that generates a directly proportional relationship between pressure and temperature, and that we could estimate this point from three simple data points.

Great job, chemists!

S'mores and Stoichiometry!

We applied the concept of stoichiometry to a popular recipe for a beloved snack, S'mores! We calculated the total masses of ingredients we would need and S'mores we would produce if we used an entire bag of marshmallows to make S'mores (which we did). Then we got to roast the marshmallows over a brand new Bunsen Burner and enjoy S'mores! (Thanks to another chemistry teacher for the picture!)

Gas Laws and Eudiometers!

We are having a great time in chemistry studying gas laws and the phases of matter!

Our chemists completed an experiment where we reacted hydrochloric acid and magnesium metal and trapped the hydrogen gas in a glass eudiometer tube. Students had to balance the equation and perfome the stoichiometry (ask your chemist what that word means!) calculations for the reaction. We also discussed what would happen to the gas if we had collected it at different temperatures and pressures.

Great job, chemists!