General Chemistry Questions & Answers

General Chemistry Questions & Answers Advantages and disadvantages of catalysts - CORRECT ANSWER- Advantages: -cost effective : less money for the catalyst than purchasing the enrgy require (temp or pressure) -reduced burning of fossil fuels : lesser temperature and pressure required through combustion of fossil fuels Disadvantages : -Most transition metals are toxic and can harm the environment Advantages of flame emission spectroscopy - CORRECT ANSWER- Rapid Sensitive Accurate Advantages of modern day fertilisers? - CORRECT ANSWER- -Can be tailored to specific situations -High availability -Odourless -Easy to use Advantages of using hydrogen fuel cells instead of rechargeable batteries - CORRECT ANSWER- -No toxic chemicals to dispose at the end of the life -No loss in efficiency over time -Travels further before refuelling Alkali metals reacting with chlorine - CORRECT ANSWER- -Flame -solid forms -colour of chlorine disappears alkali metals reacting with water - CORRECT ANSWER- lithium : light bubbling and floats on water Sodium : bubbling and fizzing produces heat to melt sodium Potassium : like sodium except the bubbling and fizzing is more rigorous alkane and alkene reaction with bromine water - CORRECT ANSWER- Alkane : nothing - saturated Alkene : colourless - spare double bond reacts with the bromine water Are catalysts used up in a reaction? - CORRECT ANSWER- -No : reusable -However catalysts needing clearing or regenerating which is harmful for the environment Atmospheric Pollutants - CORRECT ANSWER- -When sulfur is burnt in car engines, reacts with O2 inair forming SO2 SO2 reacts with water to form H2SO4 : weathers buildings, kills organisms and corrodes steel -Incomplete combustion produces CO and particulates CO binds to haemoglobin and restricts blood ability to transport oxygen