help me to start on this
28. What causes Brownian motion?
o Brownian motion is caused by _______________ of the molecules of the dispersion medium with the small, dispersed colloidal particles. These collisions help prevent the colloidal particles from ______________.
Practice Problems
1. A gas mixture containing oxygen, nitrogen, and carbon dioxide has a total pressure of 32.9 kPa. If PO2= 6.6 kPa and PN2=23.0 kPa, what is PCO2?
2. Exactly 5.00 L of air at -50.0°C is warmed to 100.0°C. What is the new volume if the pressure remains constant?
3. List three factors that can affect gas pressure.
a. Temperature
b. Volume
c. Number of particles
4. Using three complete sentences, explain why ice is less dense than liquid water.
Read here for Brownian movement.
https://en.wikipedia.org/wiki/Brownian_motion
1. Ptotal = pN2 + pCO2 + pO2
2. (V1/T1) = (V2/T2) Remember to use T in kelvin.
3. Those look ok to me.
4. Go to Google and type in why is ice less dense than liquid water. Read a lot. Look especially at the Wikipedia document.
To answer the question, "What causes Brownian motion?", we need to recognize that Brownian motion is the random movement of small particles in a fluid medium. This motion occurs due to the collisions between the molecules of the dispersion medium and the small colloidal particles.
To prevent the colloidal particles from settling down, the constant collisions provide the necessary kinetic energy to keep them suspended and in motion. These collisions are the driving force behind Brownian motion.
Now, let's move on to the practice problems:
1. To find PCO2, we need to use Dalton's law of partial pressures. According to Dalton's law, the total pressure (32.9 kPa) is the sum of the individual partial pressures of each gas. So, we can write the equation as PO2 + PN2 + PCO2 = Total pressure. Plugging in the given values, we get 6.6 kPa + 23.0 kPa + PCO2 = 32.9 kPa. Solving for PCO2 gives us PCO2 = 32.9 kPa - 6.6 kPa - 23.0 kPa.
2. Since the pressure remains constant, we can use Charles's law to solve this problem. Charles's law states that the volume of a gas is directly proportional to its temperature in Kelvin. To convert Celsius to Kelvin, we add 273.15. In this case, the initial volume is 5.00 L at -50.0°C, which is 223.15 K, and the final temperature is 100.0°C, which is 373.15 K. Using the formula V1 / T1 = V2 / T2, we can plug in the values to find the new volume.
3. The three factors that can affect gas pressure are:
- Temperature: As temperature increases, the average kinetic energy of gas particles also increases, leading to more frequent and forceful collisions with the container walls, resulting in higher pressure.
- Volume: Changing the volume of a gas can directly affect its pressure. When the volume decreases, the gas particles get closer, increasing the frequency of collisions and raising the pressure.
- Number of particles: Increasing the number of gas particles in a given volume will result in more collisions with the container walls, causing an increase in pressure.
4. Ice is less dense than liquid water due to the changes in the arrangement of water molecules. In the solid state, as water freezes and forms an ice lattice, the water molecules spread out and form a more open structure compared to the closely packed arrangement in liquid water. This change in structure leads to an increase in the volume occupied by the water molecules, while the mass of the substance remains constant. As a result, the density of ice decreases compared to that of liquid water.