osmosis lab example 2 -
Chemistry classes often include experiments and problem sets that involve calculating percent change in mass of a substance. The percent. However, the relationship between mass and volume is constant for a and pressure, density can also change with temperature and pressure. Answer to Exercise A. 1. Describe the relationship between the molarity of sucrose and the percent change in mass. 2. What effect.
The red blood cell would take in a lot of water and might lyse due to pressure inside.
This is a possibility because animal cells have no tolerance under hypotonic situations. Describe the appearance of the onion cells. The onion cells appear to have great turgor pressure, spread out, thick and bright in the inside.
The cell walls were very defined and it was clear where one cell ended and another began. Describe the appearance of the onion cells after the NaCl was added. The plasma membrane shriveled from the cell wall, causing plasmolysis. The cells looked wrinkly or weak. The turgor pressure dropped tremendously. Remove the cover slip and flood the onion with fresh water.
BBC - GCSE Bitesize: Forces, mass and acceleration
Observe and describe what happened. The onion cells were again hypertonic to their environment, and gathered water, increasing in turgor pressure and restoring themselves to the normal state of being.
Plasmolysis is the separation of the plasma membrane from the cell wall in a plant cell. Why did the onion cell plasmolyze? The environment became hypertonic to the cell and the water left the cell running with its concentration gradient due to the NaCl.
With all the water leaving the cell, it shrank, leaving behind its cell wall. In the winter, grass often dies near roads that have been salted to remove ice.
What causes this to happen. One possible source of error could be the tightness of the string that tied off the dialysis tubing.
If there was a leak or a break in the dialysis tubing, all of the data would be off. A possible source of error in this lab could have been in the first step. If the handler of the dialysis tubing did not wash their hands and accidentally touched the sac part of the tubing, the oils from their hands could have blocked some of the pores on the tubing, distorting the data.
A piece of potato skin could have been left in the beakers along with the potato. This causes problems in the data tables. Another possible source of error could be that the students did not pat dry the potato sample well enough causing drops to be left on the electronic balance, tarring it incorrectly, causing all other data to be off slightly. Simple mathematical errors always occur, so there is always room for simple algebraic mistakes in this section of the lab.
If the wet sample was not prepared correctly, or the salt solution added to fast not giving the cells time to react, this lab would have different results. The sources of error also include the possible concept that the onion cells might have dried out by the time the observer got around to sketching.
osmosis lab example 2
This could cause error in observances, and data in conclusion. During Lab 1A, the data suggests what molecules can and cannot diffuse across a selectively permeable membrane.
The coloration showed that the Iodine Potassium Iodide was small enough to pass through the pores of the membrane because the color of this indicator moved from within the beaker to in the bag. Water and glucose moved out because water is small enough to pass through the membrane and the glucose tested positive with the Testape inside the beaker.
The glucose at the beginning was only in the bag, so it obviously moved out.Why Did Vatican II Change the Form of the Mass?
Lab 1B proved that water moves across the selectively permeable membrane of the dialysis tubing much easier than sucrose sugar does. The water moved to reach equilibrium between the solutions. Sucrose must be too large a molecule to pass through the membrane quickly. Lab 1C showed that the potato samples took in water when immersed in a distilled water solution.
Mass Changes in Chemical Reactions - Activity
Potatoes must contain sucrose molecules due to the conclusion of this lab because the potatoes take in water in the distilled water beaker. Potatoes had a lower water potential and higher solute potential than the distilled water. It is just the opposite inside the beaker. This gives the lab much better illustration and a stable understanding of diffusion and osmosis.
Lab 1E showed the plasmolysis clearly and allowed the student to see exactly what goes on in this action. This particular part of the lab illustrated the shrinking of the plasma membrane from the cell wall in a plant cell. It shows how plant cells react in a hypertonic environment. Unlike mass and volume, increasing the amount of material measured does not increase or decrease density. This makes density a useful property in identifying many substances.
However, since volume deviates with changes in temperature and pressure, density can also change with temperature and pressure.
The Relationship Between Mass, Volume & Density | Sciencing
Specific Gravity One derivative measurement of density is specific gravity. Specific gravity compares the density of a substance with the density of a reference material. In the case of gases, the reference material is standard dry air, or air without water. In the case of liquids and solids, the reference material is fresh water. Specific gravity is calculated by dividing the density of a substance by the reference substance's density.
- Movement across cell membranes
- Forces, mass and acceleration
For example, gold has a density of This yields a specific gravity of This means gold is Buoyancy Whether an object floats or sinks is determined by the downward force of gravity and an upward buoyant force. If the buoyant force is greater, an object floats.
If the force of gravity is greater an object sinks. The interplay between these forces is related to the density of the object and the density of the fluid it is placed in.
If the overall density of the object is greater than the liquid, the object sinks. If the overall density of the object is less than the liquid then the object floats.