Chemistry of Metals Miss Jan

Chemical reactions of metals SLOs investigate the reactions of metals with oxygen, water, and acids write word equations and symbol equations for the common reactions of metals write chemical formulas for metal compounds understand how the atomic structure of metals can explain their chemical reactivity relate the uses of metals to their physical properties and reactivity

Worksheet [A] Metals and air (Oxygen gas) Clean metal if rusted or dirty by rubbing them with sandpaper Hold in flame using tongs Record colour of flame and the colour of the product Record reactivity: react violently, reacts rapidly, reacts, reacts very slowly, do not react

DO NOW Name 2 alloys State the uses for these alloys Why would we use alloys rather than pure metals? Brass (Cu+Zn), Steel (Fe+C), Amalgam (Hg+ another metal), Bronze (Cu+Sn) Brass – instruments, Steel – pipes, construction, Amalgam – dental fillings, Bronze – statues. Because they have different properties than the pure metals that makes them suitable for their uses. E.g. Steel and Bronze = stronger and resist rusting. Brass = malleable etc.

Many metals react with oxygen Magnesium burns brightly when heated in air. The equations are: magnesium + oxygen  magnesium oxide Mg + O2  MgO Copper reacts only very slowly when heated in air. It forms black copper oxide. The equations are: copper + oxygen  copper oxide Cu + O2  CuO Word equation 2 2 Symbol equation 2 2

Write the word and symbol equation for Al and Fe Aluminium + oxygen  Aluminum oxide Al + O2  Al2O3 Iron + oxygen  iron oxide Fe + O2  FeO 4 3 2 2 2

Colored flame

Be careful: some reactions may create HEAT!!! Worksheet Be careful: some reactions may create HEAT!!! [B] Metals and water Place small sample of metal in water Observe and record reactivity Collect gas and test with flame Record result of gas test and colour of product Record reactivity: react violently, reacts rapidly, reacts, reacts very slowly, do not react

Some metals react with water Lithium reacts rapidly with cold water to form lithium hydroxide and hydrogen gas (fizzing). The equations are: lithium + water  lithium hydroxide + hydrogen 2Li + 2H2O  2LiOH + H2

Write the word and symbol equations for the reaction of Ca with water Calcium + water  Calcium hydroxide + hydrogen Ca + H2O  Ca(OH)2 + H2

Sodium – stored in mineral oil Calcium in water

Be careful: some reactions may create HEAT!!! Worksheet [C] Metals and acid 1 cm of sulfuric acid in test tube and add a small sample of metal Observe reaction and record results in table Collect gas and test with flame Record reactivity: react violently, reacts rapidly, reacts, reacts very slowly, do not react Be careful: some reactions may create HEAT!!!

Many metals react with acids For example, zinc reacts with dilute sulfuric acid to form zinc sulfate and hydrogen gas (fizzing). The equations are: zinc + sulfuric acid  zinc sulfate + hydrogen Zn + H2SO4  ZnSO4 + H2

Summary metal + oxygen  metal oxide metal + water  metal hydroxide + hydrogen metal + acid  salt + hydrogen Pop test – if hydrogen is present, a squeaky pop would be heard if a flame is introduced Usually metals that react quickly with oxygen also react quickly with water and acids.

Activity and uses of metals Active metals like Na, Li, Ca, Mg aren’t used to make things. Common metals like Al, Zn, Fe, Pb, Cu are used to make lots of different objects. Precious metals like Ag, Au are only used in valuable objects.