Unit 9 is a unit where we took everything that we have learned this year, and applied to it to one problem or situation. For example, we learned about gases earlier this year but they appear again in this unit. In fact, we had to look back on unit 2 so that we could refresh our memory on pressure and volume when dealing with gases. Some of the things that i found helpful to review was standard pressure and temperature. Also reviewing that as volume decreases pressure increases and we call that an inverse relationship. In Unit 9 we applied these skills and made charts in order to find the volume or pressure of gases. This was demonstrated on worksheet 1.
We were then able to apply this to a lab where we found the volume of a mole of gas at standard pressure and temperature. We used a piece of magnesium ribbon, stopper and copper wire. After out calculations we were able to determine the mass of the copper wire, the volume of the gas collected and the vapor pressure of the water. All this was done by using a VNTP chart and setting up ratios to find moles. (which we have done in previous units)
After refreshing ourselves and combining past knowledge to solve problems, we then learned a new formula, PV=NRT. This formula says that pressure times volumes equals the number of moles times the constant, times the temperature of the given substance. The constant is always the same number (.0821 with liters times atm all over moles times k) without this constant we would not be able to solve for a given value. This number makes that possible. pv=nrt is a very straight forward formula that allows us to solve for a either pressure, volume, moles, or temperature when given the other values.
We were then able to apply this a balloon lab that we did in class called "The Air Bag Challenge". in this lab we had to determine how much CO2 was needed in inflate a balloon. we first did this by balancing out the equation that was given to us. And then by solving for the amount of moles we needed, we were able to successfully inflate a balloon to the right pressure so that it wasn't flat and
didn't pop.
In this unit we also learned about the concept of molarity. Molarity is the concentration of a solution given in grams and moles of a solute per liter of solution. Therefore, molarity is moles over liters in relationship to on another. Molarity allows us to calculate grams and the volume of an element by setting up proportions.
We also Applied this to a Kool- aid lab where we were able to determine the right about of Kool-aid needed for the amount of water that we were given. This was proven when we taste tested multiple cups of Kool-aid and some were very watery and others were very sweet and sour. By using molarity, we were able to determine the proper amount of moles and grams of kool-aid needed to make the best cup of kool-aid.
Overall, unit 9 brought together all the concepts that we have been learning throughout the year. The ideas of pressure, volume and moles were all brought together so that we could better understand the relationship between them. We solved many problems using math and BCA charts. This unit really helped me put all the concepts that I've learned this year and apply it not, only in my math work but in lab.
