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CH 221 Winter 2018 Lab Final l. An unknown solid is either nickel, chromium, alu

ID: 1029025 • Letter: C

Question

CH 221 Winter 2018 Lab Final l. An unknown solid is either nickel, chromium, aluminum or lithium. The unknown solid floats on water before reacting with the water. Use this information to identify the solid. Explain briefly why you chose the metal. This unknown solid is 2. Magnesium oxide has a sodium chloride octahedral-type radius of Mg2 is 79 pm, and the density of magnesium oxide is 3.56 g/em2, what is the radius of the oxide ion in Angstroms? structure of oxide ions with magnesium ions in octahedral holes. If the

Explanation / Answer

1) Density of lithium =1/2 *density of water so it floats on water before reacting with it giving off hydrogen gas and colorless solution of lithium hydroxide with slow liberation of heat.

2Li(s)+2H2O(l)--->2LiOH +H2(g)

Nickel ,chromium and aluminium has higher density than water so they do not float on water.