Lithium (Li\text{Li}Li) and sodium (Na\text{Na}Na) are two alkali metals in Group 1 of the Periodic Table. Both react with water.
State two observations that would be made when a small piece of lithium is added to water.
Sodium is more reactive than lithium. State one observation that is made with sodium but not with lithium.
Complete and balance the chemical equation for the reaction of lithium with water:
2Li+2H2O→‾+‾ 2\text{Li} + 2\text{H}_2\text{O} \rightarrow \underline{\hspace{2cm}} + \underline{\hspace{2cm}} 2Li+2H2O→+After the reaction of lithium with water is complete, a few drops of phenolphthalein indicator are added to the solution. State the color of the indicator and give the formula of the ion responsible for this color.
A sample of potassium oxide is analyzed to determine its empirical formula. In an experiment, 7.8 g7.8\text{ g}7.8 g of potassium is obtained by decomposing 9.4 g9.4\text{ g}9.4 g of this potassium oxide. [Relative atomic masses: K=39.0\text{K} = 39.0K=39.0, O=16.0\text{O} = 16.0O=16.0]
Calculate the mass of oxygen obtained from the potassium oxide during this decomposition.
Determine the empirical formula of the potassium oxide by calculating the amounts, in moles, of potassium atoms (K\text{K}K) and oxygen atoms (O\text{O}O).
