The reason you heat the test tube before weighing it is because of the residual moisture on the test tube itself. The weight of the glass itself will not change, but if there is moisture inside the tube, it could distort your readings. Therefore, you heat the test tube to evaporate any moisture remaining in the test tube to get an accurate weight measurement.
Samples are kept in the dark for 30 minutes in the determination of iodine value to prevent the oxidation of unsaturated fats by light. Exposure to light can cause the fats in the sample to undergo photooxidation, which can result in inaccurate measurement of the iodine value.
A urine sample for kidney testing can typically be kept in a plastic container at room temperature for up to 24 hours. It should be securely sealed and stored in a cool, dark place to prevent contamination or deterioration of the sample. If the sample cannot be tested within 24 hours, it is recommended to refrigerate it or use a preservative to maintain its integrity.
To prepare a sample of pure dry ammonium nitrate, dissolve ammonium nitrate in water to form a saturated solution, then allow the solution to cool and crystallize. Filter and dry the resulting crystals to obtain pure dry ammonium nitrate.
By weighing the initial amount of copper carbonate before the reaction and the final mass of the products after the reaction, you can measure the loss in mass which corresponds to the amount of carbon dioxide produced. Since mass is conserved in a chemical reaction, the lost mass must be equal to the mass of carbon dioxide released during the decomposition.
LL Cool J was the first solo rap artist to achieve platinum status with his album "Bigger and Deffer" released in 1987.
When first hatched, baby platypuses weigh less than a gram.
To calculate the amount of ice water needed to cool the sample to 20 degrees Celsius, you would need the initial temperature of the sample, the mass of the sample, and the specific heat capacities of water and ice. With this information, you could use the equation q = m * c * ΔT to determine the quantity of ice water needed to cool the sample.
- place a sample in a refrigerator- place a sample in liquid nitrogen
The best way to determine the organic content of a soil sample is the following: 1. First weigh the lab vessel that you will be putting your sample in and write it down. 2. Scoop in 5 g of the sample into the vessel then weigh it again. 3. Subtract the weight of the vessel by the weight you got in #2. This is your starting weight. 4. After adjusting the muffler furnace to 360 C, put the soil sample you have measured out that is in the lab container in the furnace for two hours. 5. After two hours, put on heat resistant gloves and take out the sample to allow it to cool. It will be very hot, much too hot to handle at the moment. 6. When it is cool, weigh the sample again, and just like in #3, subtract the weight of the vessel to this sample weight and you will get the weight of the sample without the weight of the organic matter. 7. Now divide the weight of the of the soil without the organic matter by the starting weight (which should be 5 g), then multiply by 100. This will give you the amount of soil in the sample. Now subtract by 100 from this amount and you will get the amount of organic matter in the soil. For example, If the end weight is 4.7g, then 4.7/5.0 = 0.94, which means that 0.94 x 100= 94%. Therefore, 100-94 = 6% of the soil sample is composed of organic matter.
cause its cool
because it is cool
a lot!! soak it first for about 2 hours in cool water before cooking
"Ashleys Roachclip" - by the Soul Searchers
why would you want to know that? I don't know what he weighs and I'm Tre Cool's biggest fan.
jimmmy Guerrero is cool
no but a cool fact is that you weigh less in the morning
The inoculating tube is cooled before use so that the organism is not killed by extensive heat.