Name: __________________________________ ( ) Class: 4Q HWA CHONG INSTITUTION PRELIMINARY EXAMINATION 2010 CHEMISTRY 5072 Paper 1 Time: 1 hour INSTRUCTIONS TO CANDIDATES Do not turn the pages over until you are told to do so. Write your name and index number on the answer sheet in the spaces provided. There are forty questions on this paper. Attempt all questions. For each question‚ there are four possible answers labelled A‚ B‚ C and D. Choose the one you consider correct and
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quantities (masses‚ volumes) of reactants and products involved in chemical reactions. It is a very mathematical part of chemistry. In this experiment‚ you will react a known amount of sodium carbonate solution with a known amount of calcium chloride solution. The skeletal (unbalanced) equation for the resulting double replacement reaction is: Na2CO3(aq) + CaCl2(aq) Æ NaCl(aq) + CaCO3(s) Note that three of the chemicals have their states or phases designated as (aq) and one is designated
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Reacting Acids and Bases Lab Report Introduction Every liquid‚ except for distilled water‚ has either acidic or basic traits. An acid is sour tasting‚ and gives a sharp stinging pain in a cut or wound‚ and bases taste bitter‚ and feel slippery. A pH scale is used to determine what traits a liquid has; acidic or basic. The scale focuses on OH- (hydroxide ions) and H+ (hydrogen ions). The scale goes from 0 to 14. 7 is distilled water‚ as it is directly in the middle; neither acidic or basic. Acids
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Running Head: RESPIRATORY PROTECTION SELECTION Respiratory Protection Selection Therese Kress MGT. 401 Hazardous Materials Management Instructor Stephen Griffith September 29th‚ 2014 MGT401: Hazardous RESPIRATORY PROTECTION SELECTION Respiratory Protection Selection Employers have a wide variety of Respiratory Protection gear that can be used these days to protect their workers from hazardous situations
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Diffusion and Osmosis Experiment Methods/Materials: 7.1 Experiment: Rate of Diffusion of Solutes In the initial set up of this experiment I had 2 sets of 3 screw-cap test tubes that had each been half-filled with 5% gelatin and 1-mL of the correct dye (either potassium dichromate‚ aniline blue‚ or Janus green) in each of the test tubes. I labeled the 3 test tubes of set 1 with which die they contained and marked them “5 ˚C”. Then with the other set I did the same exact thing‚ except I labeled
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the concentration affects the rate of diffusion of hydrochloric acid through agar blocks Research Question: To determine how will different concentrations (0.1M‚ 0.2M‚ 0.3M‚ 0.4M‚ 0.5M) of hydrochloric acid affect the rate of diffusion of sodium chloride through agar blocks? Introduction-include prediction; information you have researched before Diffusion refers to the passive movement of molecules along the concentration gradient. In this case we will be looking at the diffusion of acid in agar
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hydroxide (NaOH) in water affected by temperature? ! ! Introduction ! Sodium hydroxide is categorised as metal halide salt‚ composed of sodium and chlorine.! The ions present in the solid crystals of potassium chloride dissolve and gain mobility in water. When potassium chloride is dissolved in water‚ the following endothermic reaction occurs:! NaOH(s) + H2O(l) → Na+(aq) + OH–(aq) + H2O(l)! This reaction takes place because water is a polar solvent and display a permanent dipole status.
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This experiment called for determining the salinity through mass. To determine mass‚ a small‚ cleaned watch glass was labeled with the sample number on the bottom using a permanent marker. The watch glass was weighed in grams. 2 mLs of the sodium chloride solution was pipetted into a 10 mL graduated cylinder that would be transferred to the watch glass. After this transfer‚ the watch glass and sample were reweighed and recorded. To figure out the mass of the solution‚ the plain watch glass was subtracted
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pipet - 5 test tubes - mortar and pestle - test tube rack - magnet - test tube holder - insulating pad - watch glass - safety goggles - glass square - lab apron or coat - copper sulfate pentahydrate - iron fillings - sodium chloride - magnesium ribbon - hydrochloric acid - paper (5 cm x 10 cm) - silver nitarate - birthday candle - sulfur - matches Procedure: 1. Place a small amount of wax from a birthday candle into a test tube. Heat gently over a burner
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Trimethylmethanol or 1‚2‚4‚5-Tetrachlorobenzene. Introduction Extraction is a process of transferring a solute from one solvent to another. It is usually used to separate one or more components from a mixture. Diethyl ether‚ dichloromethane (methylene chloride)‚ trichloromethane (chloroform)‚ pentane‚ hexane‚ petroleum ether are some of the solvents commonly used for extracting aqueous solutions. Petroleum ether and ligroin are mixtures of hydrocarbons whereas the other liquids mentioned earlier are pure
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