Base your answers
to questions 73 through 75 on the information below.
technician is given the table below and a sample of one of the three
substances listed in the table. The technician makes an aqueous
solution with a portion of the sample. When a conductivity tester is
lowered into the solution, the light bulb on the tester glows
brightly. Another portion of the sample is placed in a
heat-resistant container that is placed in an oven at 450.oC.
The sample melts.
73 Identify the
substance given to the technician. 
|Answer==>sodium nitrate or NaNO3
74 State evidence
that makes it necessary to use more than one property to identify
the substance given to the technician. 
|Answer==> 2 substances are good conductors or 2
substances have melting points lower than 450.oC
75 Explain, in terms
of ions, why an aqueous solution of potassium chromate conducts an
electric current. 
|Answer==>The ions can move