Video Transcript
The word equation for the reaction
of lithium with water is shown below. Lithium plus water react to form
blank plus hydrogen. What compound is needed to complete
this chemical equation? (A) Lithium hydride, (B) lithium
hydrate, (C) lithium hydroxide, (D) lithium oxide, or (E) lithium dioxide.
In the word equation given, lithium
is reacting with water. Lithium is an alkali metal. An alkali metal is any element in
the leftmost group of the periodic table. The alkali metals are all the
elements in group one of the periodic table, excluding hydrogen. The alkali metals include lithium,
sodium, potassium, rubidium, cesium, and francium. One property that all the alkali
metals share is reactivity. The alkali metals react readily
with water. Upon reacting with water, alkali
metals form an alkaline solution. Let’s have a look at what the
reaction between lithium and water is like.
When lithium metal is added to
water, the reaction is fast and gives off a lot of heat. Hydrogen bubbles can be seen
forming as well. The second product is an alkaline
solution. Alkaline solutions contain
hydroxides. A hydroxide is a chemical species
that contains the hydroxy, or OH−, ion. The alkaline solution formed will
have hydroxide in the name. This alkaline solution will be
composed of hydroxide ions and lithium ions from the lithium metal.
Therefore, the name of this
compound will be lithium hydroxide. We can see that answer choice (C)
is the correct answer. So, the compound needed to complete
this chemical equation is answer choice (C), lithium hydroxide.
