What mass of MgCO3 is contained in a 2.750g solid sample consisting of only MgCO3 and MgO if heating to decompose all the MgCO3 according to the following equation leaves a solid residue weighing 2.160g? Magnesium oxide is unaffected by the heat. MgCO3(s) MgO (s) + Co2 (g) 2. a) Consider the reaction of question 2. Suppose a 3.250 g sample containing only MgCO3 and MgO is 42.6% MgO. How many grams of CO2 would be liberated by complete thermal decomposition of the MgCO3 in the sample?
The watch glass was removed with the beaker tongs. Using a rubber bulb and a stirring rod to stir the solution continuously, 15.00mL of .25M BaCl2 solution was added to the solution in the beaker. The watch glass is replaced and the solution is keep hot but not boiling for 15 minutes. The precipitate was allowed to settle. When the liquid above the precipitate was clear, the solution was tested for completeness of precipitation when a few drops of BaCl2 solution were added from a pipette.
Measure 50.0 mL of 2.0 M Sodium Hydroxide, NaOH, solution but DO NOT ADD YET. Click the Collect button to get the initial temperature of the HCl solution. After the first four readings have been recorded at the same temperature, add the NaOH solution. Make sure you have lowered the paper lid to keep from liquid coming out of the cup. Turn the Stirrer on, at a slow to medium speed.
high melting point, hard, brittle, slightly soluble in water, conductor of electricity when melted or in solution Molecular solid - crystalline solid that has molecules arranged in a particular configuration. low melting point, generally insoluble in water, nonconductor of electricity. Metallic solid - crystalline solid that has atoms of metals arranged in a definite pattern. low to high melting point, malleable, ductile, conductor of electricity, insoluble in most solvents. Lesson 13.6 Changes of physical state: * necessary to draw a temperature-energy graph to see the change in temperature with a constant application of heat Heat of fusion - the amount of heat required to melt 1.00 g of substance.
Chemical Bonding, structure and Quantity Aim To investigating a range of compound which include metallic, covalent molecular, covalent giant and ionic giant Materials used and list of apparatus Google Bunsen burner Test tube Power supply Spatula Tongs Mats Method To discover the characteristic physical properties of the substances six tests were done. These were tests of appearance, melting point, conductivity of solid, solubility in water, conductivity of solution and hardness. Test 1: Appearance. This was to note whether the substance was shiny, dull, with colour etc. Test 2: Melting point.
We know it exists but we can’t find the way to measure it. This lab teaches us how to measure the heat of neutralization when NaOH reacts with HCl. When we mix 50.0mL of 2M HCl with 51.0mL of 2M NaOH, we get 53.94 kJ/mol of heat of neutralization. Introduction: The heat of neutralization is the heat transferred when 1 mole of acid reacts with 1 mole of base. The heat is generally reported in either kilojoule per mole (kJ/mol) or kilocalories per mole (kcal/mol).
DENSITY OF ANTIFREEZE- WATER MIXTURES In this experiment, several mixtures of water and ethylene glycol (the major component of ‘’antifreeze’’) will be prepared and their densities measured. A calibration curve will be generated by plotting density versus percent antifreeze, and this curve will be used to determine the composition of an ‘’unknown’’ sample mixture. WARNING: ethylene glycol major component of antifreeze is a sweet tasting, poisonous liquid. Avoid unintentional ingestion by following standard laboratory safety measures. Step 1using a clean 10-ml pipet, transfer precisely 4.00, 3.50, 3.00, 2.50, and 2.00 ml of tap water to five separate test tubes.
The dichloromethane is then separated from the mixture in the rotary evaporator. Figure 1: The structure of caffeine is very similar to those of purine bases (adenine and guanine) in DNA, therefore caffeine is a good substance to practice on for dealing with nucleic acids. Procedure Approximately 10g of tealeaves, CaCO3 (4.8g, 0.048 mol) and deionised H2O (100mL) is added into a beaker and boiled for 15 minutes. The mixture is then cooled to 20˚C and is filtrated using a Buchner funnel (vacuum filtration). The extraction process is when a solvent, dichloromethane (15mL) is added to the filtrate in a separatory funnel; the mixture is gently swirled together 3 times, and stopcock is released in between to vent the funnel.
Recrystallization of the Benzoic Acid Antonio Roki CHE 311L: Organic Chemistry I Section #2 September 14, 2012 Recrystallization of the Benzoic Acid Summary: The purpose of this experiment was to determine if the process of the Recrystallization is the good method of purification of the solid substance based on its different solubility values. This experiment conducted the purification of the Benzoic acid. The melting point range of the impure Benzoic acid was determined to be 86- 108 °C. Melting point was measured one more time after the process of the purification and was determined to be 111-117 °C. The melting point ranges of the impure and pure benzoic acid seemed reasonable.
The reaction was monitored and removed from the heat once the effervescence ceased, and then was allowed to cool. Concentrated hydrochloric acid was added while heating and stirring the reaction for 15 minutes. The product was then allowed to cool and was vacuum filtered to a maroon color, while being washed with water, 6M hydrochloric acid, ethanol, and acetone. Then allow the product to dry for five minutes on the funnel. The resulting product was [Co(NH3)5Cl]Cl2 and yield was 4.453g (.017 mol, 84.8%) Distilled water (25mL) was added to concentrated ammonia (5mL) in a 125mL Erlenmeyer flask.