Weighing paper

In conventional preparative TLC, after the separation the. bands are visualized and the separated zones carefully marked for removal. The zones are scraped off the plate with a spatula similar tool onto glassine weighing paper. A number of devices based on the vacuum suction principle are commercially available ... 

Measure the mass of a piece of weighing paper to 0.1 g using a laboratory balance. Record this mass in Data Table 1. 

Add about 5.0 g of table salt from the 50-mL beaker to the weighing paper. Record the mass of the weighing paper and table salt to 0.1 g in Data Table 1. 

To find the Mass of table salt, subtract the Mass of weighing paper from the Mass of table salt + weighing paper. ... 

Measure 5 g of ammonium chloride (NH4C1) crystals on a piece of weighing paper. Carefully pour the ammonium chloride from the weighing paper into the water in the foam cup. Cautiously without splashing, stir the solution with a clean stirring rod. 

How can you make a polyester and a polyamide Objectives Prepare a polyester from phthalic anhydride and ethylene glycol. Prepare a polyamide from adipoyl chloride and hexamethylenediamine. phthalic anhydride (2.0 g) sodium acetate (0.1 g) ethylene glycol (1 mL) 5% adipoyl chloride in cyclohexane (25 mL) 50% aqueous ethanol (10 mL) 5% aqueous solution of hexamethylenediamine (25 mL) 20% sodium hydroxide (NaOH) (1 mL) scissors copper wire test tube test-tube rack 10-mL graduated cylinder 50-mL graduated cylinder 150-mL beakers (2) ring stand clamp Bunsen burner striker or matches balance weighing papers (2)... 

Using a laboratory balance, measure the mass of a second piece of weighing paper and record the mass in Data Table 1. Place 0.1 g of sodium acetate on the weighing paper and record the combined mass. Calculate the mass of sodium acetate and record this value in Data Table 1. Place the sodium acetate in the test tube containing the phthalic anhydride. 

The alloy powder (used in hydrogen-storage systems) may ocasionally be pyrophoric after hydriding-dehydriding operations, igniting when placed on a combustible surface (e.g. weighing paper). 

Glass and quartz cuvets Weighing paper and boats... 

While dispensing and weighing a small amount of the dried sample contained in the weighing bottle, it is prudent to avoid contacting the sample with laboratory utensils or weighing paper in order to avoid loss of a portion of the sample, which might adhere to the utensil or paper. In such instances, weighing by difference is recommended. 

What is the advantage to weighing by difference, as opposed to weighing using a spatula and weighing paper ... 

Weigh between 0.10 and 0.13 g of the macaroni sample on the analytical balance using weighing paper. Add this sample to a clean, dry 100-mL Kjeldahl flask to avoid having sample particles stick to the neck of the flask. Set aside for a few minutes (inside a beaker so that it stays upright) while you do step 4. 

To say a balance has the tare feature means that the balance can be zeroed with an object, such as a piece of weighing paper, on the pan. This helps to obtain the weight of a chemical directly without having to obtain and subtract the weight of the weighing paper. 

Materials 150-mL beakers (2) 100-mL graduated cylinder stirring rod (2) spatula (2) weighing paper (2) NaOH Epsom salts (MgS04-7H20) distilled water balance... 

Materials balance, weighing paper, 250-mL beakers (2), pieces of chewing gum (2),... 

Unwrap two pieces of chewing gum. Measure the mass of each separately on a piece of weighing paper. Label the weighing papers with the masses to avoid mixing up your data. Record the masses. 

Measure approximately 2 g of iron metal filings onto a piece of weighing paper. Measure and record the exact mass of the filings. 

Materials salicylic acid, methanol, distilled water, 10-mL graduated cylinder, Beral pipette, 250-mL beaker, concentrated sulfuric acid, top or bottom of a petri dish, cotton ball, small test tube, balance, weighing paper, hot plate, test-tube holder... 

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