Answer: A.) Removing a few marbles from the petri dish and stirring the rest around as energy is added
B) The high temperature makes the gas molecules spread apart according to Charles's law because this law describes how a gas will behave at constant pressure.
Explanation: The phase transition from solid to liquid involves the use of energy to make the molecules present in solid to break the inter molecular forces and to start moving away from each other as in liquid. The molecules in solid are closely packed whereas in liquids they are loosely packed. Thus less number of molecules are present per unit volume in a liquid. Thus the marbles have to be removed to show less density and the energy has to supplied. Removing all but two marbles from the petri dish and shaking them vigorously as energy is added will give us a more disorderd state called gas in which the molecules are very far apart and the density is least.
B) According to Boyle's law the pressure is inversely proportional to the volume of the gas at constant temperature and constant number of moles.
(At constant temperature and number of moles)
According to Charle's law the volume is directly proportional to the temperature of the gas at constant pressure and constant number of moles.
(At constant pressure and number of moles)
Thus as temperature of the gas increases , the volume also increases, and the density decreases. the gas becomes lighter and thus rises up.
Answer:
A. 0.2395 w/w %
B. 2394ppm
Explanation:
A. To find concentrationin percent by mass of the solution we need to calculate mass of glycerol and mass of water. The formula is:
Mass glycerol / Total mass * 100
<em>Mass glycerol:</em>
The solution is 2.6x10⁻²moles / L. As there is 1L of solution there are 2.6x10⁻² moles of glycerol. In mass (Using molar mass glycerol: 92.09g/mol):
2.6x10⁻² moles of glycerol * (92.09g / mol) = 2.394g glycerol
<em>Mass of water:</em>
998.9mL and density = 0.9982g/mL:
998.9mL * (0.9982g/mL) = 997.1g of water.
That means percent by mass is:
% by mass: 2.394g / (997.1g + 2.394g) * 100 = 0.2395 w/w %
B. Parts per million are mg of glycerol per L of solution. As in 1L there are 2.394g. In mg:
2.394g * (1000mg / 1g) = 2394mg:
Parts per million: 2394mg / L = 2394ppm
Answer:
The cell membrane's main trait is its selective permeability, which means that it allows some substances to cross it easily, but not others. Small molecules that are nonpolar (have no charge) can cross the membrane easily through diffusion, but ions (charged molecules) and larger molecules typically cannot. A concentration gradient is a just a region of space over which the concentration of a substance changes, and substances will naturally move down their gradients, from an area of higher to an area of lower concentration.
In cells, some molecules can move down their concentration gradients by crossing the lipid portion of the membrane directly, while others must pass through membrane proteins in a process called facilitated diffusion.
Explanation:
there are your two reasons molecules cannot pass easily through the cell membrane and what part of the cell membrane helps them get through is concentration gradient
Answer:
the red blood cells
Explanation:
white blood cells fight off infection
