552 results found

#### Determining the mass of calcium carbonate obtained

Lab Experiment 2: Determining the mass of calcium carbonate obtained Purpose: The purpose of the experiment was to investigate the mass of calcium carbonate obtained from the reaction between calcium chloride and sodium carbonate. Apparatus: - Three beakers (250 - ml) - Spatula - Balance ± 0.1g - Filtration setup - Filter paper - Stirring rod - Plastic wash bottle Materials: - Sodium Carbonate - Calcium chloride - Distilled water Procedure . Weigh out 4.0g of calcium chloride (111g/mol) and dissolve in enough distilled water. 2. Weigh out 6.0g of sodium carbonate (106g/mol) and dissolve in enough distilled water. 3. Pour the sodium carbonate solution into the beaker containing calcium chloride solution. 4. Stir the mixture. Set up the filtration apparatus. Weigh the filter paper and then filter the mixture. Rinse the beaker and empty the contents in the funnel. Wash the precipitate with distilled water several times. 5. Place the filter paper with the precipitate and leave it to dry out. After it is completely dry, then weigh the dry filter paper with the precipitate. Data Table: Measurements taken in the experiment Mass of the filter paper 2.00g ±0.01g Mass of filter paper with the precipitate (after filter paper dried) 5.10g ±0.01g Mass of precipitate 3.10g ±0.01g* *The mass has an error of (±0.01) because of the reading in the mass, in

• Word count: 983
• Level: International Baccalaureate
• Subject: Chemistry

#### The Drop of Water

THE DROP OF WATER Jane Shores Jennifer Nguyen Meika Ellis Science 10 IB Mr. Cooper February 16th '06 .0 Aim: The purpose of this lab is to determine the volume of a drop .1 Problem: How can one, using a 1 ml pipette, ascertain the volume of one drop of water (dihydrogen oxide)? .2 Hypothesis: If you fill a 1 ml pipette with water and allow the water to drip through the opening, slowly enough to count each drop, then you can infer the approximate volume of a drop of water because according to the metric system, commissioned by the Academy of Science in 790, one millilitre of water is equivalent to one gram of water. Therefore, by using weight and the number of drops produced, one can figure out the volume a single drop. .3 Variables Independent: 1ml pipette Dependant: The approximate volume of a drop of water Controlled: The size of the drops, the volume of water placed in pipette All of the relevant variables identified in this lab are quantitative. The 1ml pipette is vital to this lab because it is the instrument that we intend to utilize to form drops of water from 1ml of water. The volume of a drop of water is the responding variable because in this experiment, we are trying to determine a successful method for discovering the volume of a drop of water, so if we can successfully determine the volume of a drop of water, then our experiment has proved my

• Word count: 1605
• Level: International Baccalaureate
• Subject: Chemistry

#### Water of crystallization of BaCl2.xH2O

DETERMINING THE EMPIRICAL FORMULA OF HYDRATED BARIUM CHLORIDE BaCl2 * DESIGN: Introduction: Water of crystallization is water in the structure of a crystal but not chemically bonded to the host molecule. Hydrates are compounds that contain water molecules in their solid crystalline form, e.g. CuSO4.5H2O or CaSO4.2H2O. Usually, a defined number of water molecules are associated with each unit of the primary substance. Barium chloride BaCl2 is a hygroscopic ionic chemical compound, which attracts water molecules in its surrounding environment. In this experiment, we try to determine the number of water molecules in each molecule of the sample. Question: What is the empirical formula of crystallized barium chloride BaCl2.xH2O, in other words, in what ratio is barium chloride and water in the hydrate? Hypothesis: The most common form of crystallized barium chloride is BaCl2.2H2O. It is possible that the sample barium chloride in the lab also has the same empirical formula, which means there are 2 molecules of water associated with each molecule of BaCl2. Variables: Independent variable: The mass of hydrated barium chloride (BaCl2.xH2O) Dependent variable: The mass of anhydrous barium chloride (BaCl2) Control of variables: Controlled variable Possible way of controlling The content of the crucible Make sure there is no other mass loss than the loss of water by

• Word count: 1860
• Level: International Baccalaureate
• Subject: Chemistry

#### The Devastating Nuclear Weapon

The Devastating Nuclear Weapons During the World War 2, America started building nuclear bombs and dropped them on the Japanese cities Hiroshima and Nagasaki. The bombs killed many people, and destroyed all the surroundings. There should be no nuclear weapons in our world because they are highly destructive, inhumane and make our world unsafe. First, nuclear weapons are highly destructive devices. When a nuclear bomb explodes it has three main effects: thermal heat, radiation and a high-speed blast wave. The temperature of the heat in the fireball of the explosion is somewhere between 1-10 million degrees Celsius. This heat spreads and burns everything in its way. Many people die from burns after a nuclear bomb explosion. The radiation is a second effect of the nuclear bomb. 'People exposure within 500 meters of ground zero was fatal. People exposed at distances of 3 to 5 kilometers later showed symptoms of aftereffects, including radiation-induced cancers.' (1) The blast is one of the most destructive effects of the nuclear bomb. '90% of the city was leveled by the 500 mile an hour wind of the blast, which charred the victims' skin two miles away and incinerated those directly below the detonation.' (2) These were the effects of the bomb dropped on Hiroshima. The bombs now are much more powerful and corrosive. Second, the nuclear bombs are inhumane. It is considered okay

• Word count: 630
• Level: International Baccalaureate
• Subject: Chemistry

#### rate of evaporation

RESEARCH QUESTION How does different type of liquids affect the rate of evaporation of the liquids? HYPOTHESIS The stronger the intermolecular force, the slower the rate of evaporation Hydrochloric acid is the acid with the lowest rate of reaction compared to the other two acids, phosphoric acid and sulphuric acid. This is because HCl is a strong acid. It dissociates easily in water to form hydrogen and chloride ions. Strong acid means that HCl has strong covalent bond. So, it requires a lot of energy to break the bonds between the hydrogen and chloride ions. VARIABLES . Manipulated variable: types of solution used ; HCl [0.1 mol) , H3PO4 [0.1], H2SO4 [0.1] 2. Responding variable: time taken for the solution to evaporate 3. Controlled variable: 1) volume af the acid * Only a little acid is needed as it have a strong intermolecular forces. 2) surface area of the evaporating dish * the surface area used is the same that is in the petri dish. 3) concentration of the acid * The concentration used for the acid is the same that is 0.1M 4) temperature * the temperature for the water bath is fixed to 60°c 5) air humidity * the experiment was carried out in the same place that have the same humidity MATERIALS AND APPARATUS Materials/ apparatus Quantity/ volume Size/ concentration Hydrochloric acid, HCl 5ml 0.1 M Sulphuric acid, H2SO4 5ml 0.1 M

• Word count: 816
• Level: International Baccalaureate
• Subject: Chemistry

#### Determination of the purity of commercial aspirin

DETERMINATION OF THE PURITY OF COMMERCIAL ASPIRIN Student: Vu Cuong Nguyen Lab partner: Tianren Yang Due date: Monday September 10th 2007 I. Aim: To determine the purity of commercial aspirin by performing the reaction between sodium hydroxide and aspirin. II. Data collection: Table 1.Titration of Aspirin Run 1 Run 2 Run 3 Initial volume of NaOH (±0.05ml) 2.65 23.45 22.70 Final volume of NaOH (±0.05ml) 23.45 34.15 33.50 Amount of NaOH used (±0.1ml) 0.8 0.7 0.8 Mass of Aspirin (±0.0005g) 0.2060 0.2020 0.2000 Volume of ethanol using (±0.1ml) 5.0 5.0 5.0 Table 2.Observation Process State of solution Obtained ethanol in the conical flask Colorless Dropped aspirin powder into ethanol white and pink Added bromthyol into the solution yellow The solution was titrated by sodium hydroxide light blue III. Data processing: CH3COOC6H4COOH NaOH Mole ratio: 1 : 1 Run 1: % errormass of aspirin = naspirin (theoretical) = VNaOH (used) = (23.45 ± 0.05ml) - (12.65 ± 0.05ml) = 10.8 ± 0.1ml % errorvolume of NaOH used = × 100% = 0.9% nNaOH = (0.0108 L ± 0.9%) × 0.1 mol/L = 0.00108 mol ± 0.9% --> naspirin (actual) = nNaOH = 0.00108 mol ± 0.9% Percent purity = Run 2: % errormass of aspirin = naspirin (theoretical) = VNaOH (used) = (34.15 ± 0.05ml) - (23.45 ± 0.05ml) = 10.7 ± 0.1ml % errorvolume of NaOH

• Word count: 650
• Level: International Baccalaureate
• Subject: Chemistry

#### experiment Hess Law

Name : Mohd Haziq Al-Hakim Bin Hamirruddin Class : M08F Date : 9 July 2009 Practical : 16 Data Collection and Processing Part A:- Mass of magnesium ribbon = 0.2836 ± 0.0001g Volume of 0.5 M of HCl = 50.0 ± 0.5 cm3 Reactant Initial Temperature, ± 0.5°C Highest Temperature, ± 0.5°C Mg + HCl 27.0 40.5 Table 1 shows the initial and highest temperature for reaction between Mg and HCl To calculate the change in temperature, the following equation will be used:- Reactant Change in Temperature, ± 1.0°C Mg + HCl 3.5 Table 2 shows the change in temperature for reaction between Mg and HCl Equation for part A:- Mg (s) + 2HCl (aq) --> MgCl2 (aq) + H2 (g) Mole of magnesium Mole of hydrochloric acid = mass = MV RMM 1000 = 0.2836 g = 50.0x0.5 24.3 1000 = 0.0118 mol = 0.025 mol Thus, the limiting reagent is magnesium Heat released in the reaction can be calculated by the formula: Q = mc?T Whereby; m = Mass of the solution c = Specific heat of water (4.2 Jmol-1°C-1) ?T = Change in temperature Enthalpy change of the reaction can be determined by the formula:- ?H = Amount of heat released/absorbed, Q Number of moles of reactant, n Calculation: Heat change, Q = mc?T = 50g × 4.2 Jmol-1°C-1 × 13.5 °C = 2835 J ?Hrxn = -2835_ 0.0118 = -240.25 kJmol-1 Uncertainties: Mass = = 1.0 % Temperature = = 7.4

• Word count: 762
• Level: International Baccalaureate
• Subject: Chemistry

#### Rates of Reaction Lab

Rate of Reaction Design Experiment Effect of concentration on the rate of reaction between a metal and an acid Introduction In chemistry, chemical kinetics is the study of the factors affecting the rate of a chemical reaction. By definition, rate is the increase in the concentration of one of the products per unit time or decrease in the concentration of one of the reactants per unit time. Many factors trigger the rate of reaction, such as concentration, surface area and temperature. I will investigate the effect of concentration on the rate of reaction between a metal, zinc (Zn), and an acid, hydrochloric acid (HCl). According to the collision theory and based on my experimental results, I will prove my following hypothesis to either be correct or incorrect in theory. Design (D) Aim To investigate the effect of concentration of HCl on the rate of reaction of zinc (Zn)) by measuring the volume of hydrogen produced. Hypothesis As the concentration of the hydrochloric acid (HCl) is increased, the rate of reaction per unit time will increase up to a certain concentration too, until an increase in the concentration of the acid will no longer effect the reaction rate. According to the collision theory, the more concentrated the reactants the more collisions there will be per second per unit volume. As the reactants get used up, their concentration decreases. This

• Word count: 2387
• Level: International Baccalaureate
• Subject: Chemistry

#### Teflon. This essay will discuss the uses of Teflon, and the myths and truths surrounding it.

STAGE 2 CHEMISTRY SOCIAL & ENVIRONMENTAL RELEVANCE TASK 2 CORNERSTONE COLLEGE Name: NATALIE BAMPTON Topic: TEFLON INTRODUCTION: Teflon is also known as polytetrafluoroethylene and can be found in cookware, electronics, aeronautics and clothing. It was invented by accident by Roy Plunkett, who was originally supposed to invent a CFC gas refrigerant for the company DuPont(tm). He was investigating a substance called TFE as an alternative to toxic refrigerants such as ammonia and sulphur dioxide. Since TFE is expensive, he froze it to keep it safe. While experimenting one day, he tried to empty one of the supposedly full canisters of TFE, when nothing came out. He opened the canister to find the TFE had polymerised into a white powder, because of the high pressure and low temperature. The waxy substance was Teflon; it was slippery, non-corrosive and chemically stable, which was a breakthrough for DuPont(tm) and the rest of the world. However, recent studies have shown that Teflon may be toxic or is even likely to cause cancer. This essay will discuss the uses of Teflon, and the myths and truths surrounding it. CHEMISTRY: Polytetrafluoroethylene is a long chain of tetrafluroethylene monomers bonded to each other. It is a carbon chain backbone with two fluorine atoms attached to it. In a monomer tetrafluroethylene unit, a carbon is double bonded to another

• Word count: 1019
• Level: International Baccalaureate
• Subject: Chemistry

#### Preparation of Aspirin Lab

The Preparation of Aspirin Lab Calculating the Percent Yield of Aspirin Mass of salicylic acid +/-0.0001 g Volume of Acetic Anhydride +/- 0.05 mL Mass of Filter Paper +/- 0.0001 g Mass of Filter Paper & Aspirin +/- 0.0001 g Mass of aspirin +/- 0.0002 g Relative Molecular Mass of Salicylic Acid +/- 0.0000 g/mol Relative Molecular Mass of Aspirin +/- 0.0000 g/mol Theoretical Yield of Aspirin +/- 0.000001 g Percent Yield of Aspirin +/- 0.0002 % .0167 2.08 0.6499 .2305 0.5806 38.1216 80.1582 .326127 43.7816 Observations: After sulfuric acid was added, the solution fumed and heat up. After all of the reactants had reacted, a colorless solution was formed. After the solution was allowed to cool down and condense, the solid product that was filtered was white and in powder form. The aqueous solution left over was colorless. Sample Calculations: Relative Molecular Mass of Salicylic Acid: Mass of carbon: 12.011 g/mol Mass of oxygen: 15.999 g/mol Mass of hydrogen: 1.0079 g/mol Mass of Salicylic acid: 7 (12.011) + 3 (15.999) + 6 (1.0079) = 138.1216 +/- 0.0000 g/mol Relative Molecular Mass of Aspirin: Mass of carbon: 12.011 g/mol Mass of oxygen: 15.999 g/mol Mass of hydrogen: 1.0079 g/mol Mass of Aspirin: 9 (12.011) + 4 (15.999) + 8 (1.0079) = 180.1582 +/- 0.0000 g/mol Theoretical Yield of Aspirin: Mass of Salicylic Acid: 1.0167 +/- 0.0001 g Relative

• Word count: 1115
• Level: International Baccalaureate
• Subject: Chemistry