Kelly Pocian

Over the course of the past couple weeks we have been focusing on four main ideas. The relationship between Pressure, Volume, Temperature, and Number of Particles. These four things are represented by different units.

Pressure is measured in atmospheres (atm), pounds per square inch (psi), millimeters of mercury (mmHg), and kilopascals (kPa). 

            -Standard Pressure (at O*C): 1atm=14.7 psi=760 mmHg=101.3 kPa            - The pressure of a room (Proom) is at 730 mmHg

Volume is measured in centimeters cubed (cm^3), milliliters (mL), and liters (L).\

Temperature is measured in degrees Fahrenheit (*F), degrees Celsius (*C), and Kelvin (K). The form of measurement we want to use is Kelvin, as it will give us a more accurate representation of changes coinciding with the other factors. Celsius -----> Kelvin = *C+273
           

The Number of Particles (n) measured in puffs, the actual number of particles, or multiple units of a certain amount of particles. 

Through a series of labs conducted, we identified the relationships between pressure and the remaining three factors: Pressure vs. Volume, Pressure vs. Number of Particles, and Pressure vs. Temperature.

1: Pressure vs. Volume: In this lab we used a Pressure sensor and syringe. We filled the syringe with 5.8 mL of air particles and compressed these particles/expanded the volume of the syringe given our instructions. We found that this was an inverse relationship, as when the Volume was decreased the Pressure increased, the constant is found by using the formula k= P/V

                                                                   

                                                                       Results

    Volume (mL)       Pressure (kPa)      Constant (k=PV)
       5.8                       190.54                         1100
       9.8                       104.80                         1000
      11.8                       86.91                          1030
      13.8                       76.49                          1060
      15.8                       65.07                          1030
      17.8                       58.85                          1010
      19.8                       52.78                          1050

     


2: Pressure vs. Number of Particles: In this lab we once again used the Pressure sensor and a syringe. In this case a puff is used in the measurement of the number of particles. We took the syringe and filled it to a certain mL marking, with every 2 mL the number of particles went up one "puff". We then attached the syringe to the pressure sensor and compressed this amount of particles into 10mL. Thus, we examined how the amount of particles affected the pressure if  both the temperature and volume remained constant. We found that the relationship between Pressure and Number of Particles is a direct relationship, as when the number of particles increases, in turn, so does the pressure.

                                                                    Results

Number (Puffs)              Pressure (kPa)                    Constant(k=P/n
          1                                 27.11                                      27
          2                                 44.59                                      22
          3                                 63.58                                      21
          4                                 80.80                                      20
          5                                 99.52                                      20
          6                                117.35                                     20
          7                                136.89                                     20




3: Pressure vs. Temperature: In this lab we attached the pressure sensor to a glass flask. We had four beakers ranging in temperature from ice-water to boiling. We placed the flask in all four, measuring the temperature of the water and the pressure exerted by the air particles inside the flask when heated. Through this experiment we were able to analyze the effect of temperature on pressure. We found the relationship between Pressure and Temperature to be a direct one, for as the Temperature increases, so does the pressure.
                                                           
                                                                     Result

    Water      Pressure      Temp (*C)     Temp (K)    Constant(k=P/T)

     Ice           94.35           10.4                283.4                0.333
    Room       98.28           21.7                294.7                0.333
    Warm      102.46          42.0                317.0                0.323
    Boiling    110.66          79.0                352.0                0.314

How does a straw work?

As your lungs expand  the pressure inside your mouth lowers, as there is more space to occupy and not as many particles, creating a near perfect vacuum. As particles move from an area with higher pressure to an area with lower pressure, the particles inside the, lets say, juice pouch move into your mouth, as the pressure inside your mouth is less that the pressure inside the pouch. 

                         How does a Thermometer work?

As the liquid inside the thermometer is heated, thus making the particles move faster and expand, by expanding they must take up more space, therefore they travel up the tube, as there is more space there to occupy.