Answer:
a) 0.4004 mL : 4 significant figures
b) 6000 g : 1 significant figure
c) 1.00030 km : 6 significant figures
d) 400. mm : 3 significant figures
Step-by-step explanation:
Significant figures or digits of a number refers to the trapped zeros or the non-zero digits that have meaning and contribute to the precision of the number.
a) 0.4004 mL : 4 significant figures, zeros between the non-zero digits are the significant digits and leading zeros are not significant.
b) 6000 g : 1 significant figure, trailing zeros are not considered significant.
c) 1.00030 km : 6 significant figures, trailing zeros in a decimal number are significant.
d) 400. mm : 3 significant figures, decimal after the number indicates three significant figures.