Asolution contains cr3+ ions. the addition of 0.063 l of 1.50 m naf solution was needed to completely precipitate the chromium ions as crf3(s). what was the mass of cr3+ ions in the original solution?

Cr{3+} + 3 NaF → CrF3 + 3 Na{+} 

First calculate the total mols of NaF. 

(0.063 L) x (1.50 mol/L NaF) = 0.0945 mol NaF total 

Using stoichiometric ratio:

for step 7 table c on the lab "newtons law of action"   the average time it took the car to travel .25 meters   was 1.92 seconds.

the average time it took the car to travel 0.50 meters was 2.61 seconds

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