Jawapan

2015-08-12T21:27:44+08:00
NeutralisationYou need to be able to describe the reactions of hydrochloric acid and sulfuric acid with metal hydroxides, metal oxides and metal carbonates.Metal hydroxidesMetal hydroxides, such as sodium hydroxide, usually dissolve in water to form clear, colourless solutions. When an acid reacts with a metal hydroxide, the only products formed are a salt plus water. Here is the general word equation for the reaction:acid + metal hydroxide    →    a salt + waterYou usually observe these things during the reaction:there is a temperature risethe pH of the reaction mixture changesMetal oxidesSome metal oxides, such as sodium oxide, dissolve in water to form clear, colourless solutions. Many of them are not soluble in water, but they will react with acids. Copper(II) oxide is like this. When an acid reacts with a metal oxide, the only products formed are a salt plus water. Here is the general word equation for the reaction:acid + metal oxide    →    a salt + waterYou usually observe the same things during the reaction that you observe with metal hydroxides.Metal carbonatesAlthough sodium carbonate can dissolve in water, most metal carbonates are not soluble. Calcium carbonate (chalk, limestone and marble) is like this. When an acid reacts with a metal carbonate, the products formed are a salt plus water, but carbon dioxide is also formed. Here is the general word equation for the reaction:acid + metal carbonate    →    a salt + water + carbon dioxideYou usually observe bubbles of gas being given off during the reaction. You can show that the gas is carbon dioxide by bubbling it through limewater: this turns cloudy white when it reacts with carbon dioxide.