nature of substances

nature of pumps1. character of subject matters Simple particles match faster than complex particles. In complex jettyecules more bonds hold up to be broken. This instrument more expertness is needed to nominate the trigger off complex. Particles such(prenominal) as atoms or ions in ascendent react more quickly than complex molecules.Surface area of reactants The great the come up area of the reactants the faster the answer will take place. This is because a greater surface area means more collisions between reacting particles. When a affectionateness is ground into a powder this pluss its surface area.C at oncentration of reactants (or pressure of gun for hirees) An increase in niggardliness increases the rate of a reaction. The increased concentration means more collisions between reacting particles.Temperature An increase in temperature increases the rate of a reaction. At a higher temperature particles move faster and have more energizing slide fastener. When pa rticles collide they do so with enough energy to r from all(prenominal) one the activated complex. Heating a reaction means there will be a larger sum of collisions and more of these collisions will be effective. A temperature increase of 10C, will double the rate of a reaction. make use of of Catalysts A catalyst is a substance that will speed up a reaction without undergoing any permanent transmute. Catalysts lower the activation energy in a reaction by holding particles onto their surface and pointing them in the correct direction for a product to form. A substance that slows bug out a chemical reaction and makes it harder for a product to form is called an inhibitor.2. The experimental condition quantitative approach (the determination of the absolute or relative copiousness (often expressed as a concentration) of one, several or all contingent substance(s) present in a have.) is often employ in parity (or contrast) with qualitative approach, which seeks information ab out the identity or form of substance present. For instance, a chemist might be given an un cognize good sample. He or she will use qualitative techniques (perhaps NMR or IR spectroscopy) to identify the compounds present, and wherefore quantitative techniques to determine the count of each compound in the sample. Careful procedures for recognizing the presence of diametrical metal ions have been developed, although they have largely been replaced by modern instruments these are requireively known as qualitative inorganic analysis. Similar tests for identifying organic compounds (by testing for different functional groups) are also known.Many techniques groundwork be apply for either qualitative or quantitative measurements. For instance, suppose an power solution changes colour in the presence of a metal ion. It could be apply as a qualitative test does the indicator solution change colour when a drop of sample is added? It could also be used as a quantitative test, by stud ying the colour of the indicator solution with different concentrations of the metal ion. (This would probably be done development ultraviolet-visible spectroscopy.)3.To ensure no residue is left to affect further experiments by either contamination or to ensure a powder is non ruffleed.4. a) Litmus Paper is a paper containing dyes which change colour when receptive to unpleasants or bases. It is used to identify savage and basesb)A mixture of 10-15 natural dyes obtained from lichens (mainly roccella tinctoria) that turns red in response to acidic conditions (pH 7). When the pH is neutral (pH = 7) and so the dye is purple.c)To allow the litmus paper to absorb the pH of a solid object.5. Precipitation is the formation of a solid in a solution during a chemical reaction. When the reaction occurs, the solid formed is called the precipitate, and the perspicuous remaining above the solid is called the supernate.6. Mix acid with water, water first of all and next acid. The reas on is that when you mix acid to water the concentration of the acid is immediately diluted by water and the gradient or the concentration difference between the water and the acid keeps decreasing gradually so is the liberation of heat and is safer. Mixing concentrated acid and water is exceedingly exothermic in some cases the amount of heat generated kindle flat boil. So if you add water to the concentrated acid the small amount of water will instantly boil and splatter hot acid all over the place. Some acids will generate Hydrogen gas and will ignite and explode. If you add the acid to the water the water can absorb most of the heat and it wont splatter or explode. 7. unprovoked the match first. If one was to turn the gas valve on before rubor the match, then the gas could build up and cause an explosion once the match is lit. This is why it is important to light the match first then turn on the gas valve.8. a) To test for the presence of oxygen gas, collect a sample of the g as in a small container such as a test tube. Light a wooden care for. blunder out the flame, but make sure that the tip of the treat has a reddish, zealous tip. Insert the glowing splint into the express of the test tube.If the glowing splint bursts into flame, the gas is oxygen. b) To test for the presence of hydrogen gas, collect a sample of the gas in a small container such as a test tube. Light a wooden splint, but do not blow out the flame. Insert the burning splint into the mouth of the test tube.If the gas is hydrogen, you will hear a slight fickle pop sound. c) To test for the presence of speed of light dioxide gas, collect a sample of the gas in a small container such as a test tube. Add a small amount (2 to 3 ml) of birdlime water to the test tube and shake the test tube to mix the gas and the lime water.If the lime water solution turns a milklike white, the gas is cytosine dioxide.This test works because lime water and carbon dioxide gas react to form a white pr ecipitate.A bet on test is to light a wooden splint. Place the burning splint into the mouth of the test tube.If the flame is extinguished, the gas may be carbon dioxide.Since carbon dioxide is neither explosive nor does it support combustion, placing a burning splint into the mouth of the test tube containing carbon dioxide extinguishes the flame. This second test is not a positive test for carbon dioxide however since other gases may also extinguish a flame since they too do not support burning. Therefore, the first test is better.9. Place an Alka Seltzer tablet in the bottom of a balloon or plastic sandwich bag. get out the encased tablet tightly with a natural rubber band or string, then fill the remainder of the balloon or bag with water and seal it with another rubber band or a pick of string. Carbon dioxide gas can be produced by loosening the rubber band or string around the tablet and allowing the water to gravel the tablet.10. Oxygen11. a) A balanced equation contain s equal numbers of each element on the reactant and on the product side of the equation.b) i) (s) Solid ii) ( ) iii) (g) vapourish iv) (ag) Aqueous f v) ( ) kjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj g vi) ( ) kjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj g vii) ( = )12.a) A chemical reaction in which heat is absorbed, because the products are higher in energy than the reactants b) A chemical reaction in which heat is released, because the products are of lower energy than the reactants c) Redox (shorthand for reduction-oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. This can be either a simple redox act upon such as the oxidation of carbon to yield carbon dioxide or the reduction of carbon by hydrogen to yield methane (CH4), or it can be a complex process such as the oxi dation of sugar in the human body through a serial publication of very complex electron transfer processes. d) Thermal decomposition, also called thermolysis, is outlined as a chemical reaction when a chemical substance breaks up into at least two chemical substances when heated. The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. e) f)13. 1 dm = cm = m = ml = l14. a) b) Litres (l) or cubic metre (m3) c) d) e) f) Second (s) g) Kilogram (kg) h) Grams per mole (g/mol or gmol-1)