Significant Figures

1. Determine the number of significant figures in the following measurements:

• (a) 30.240 cm have?
  
  3 4 5

• (b) 0.00545 g have?
  
  3 4 5

• (c) 1.00040
  
  3 5 6

2. Perform the arithmetic operation and round off the answers to the correct number of significant figures:

• (a) (0.0022 g)/(3.45 mL)
  

  6.377 x 10^-4 g/mL
  6.4 x 10^-4 g/mL
  6.38 x 10^-4 g/mL

• (b) 84.35 g - 0.02345 g
  

  8.4 x 10¹ g
  84.3266 g
  84.33 g

• (c) 65.5 g / (54.45 cm x 65.45 cm x 65.0006 cm)
  

  0.000283 g/cc
  0.00028 g/cc
  0.00 g/cc

3. Express the following in scientific notation to three significant figures:

• (a) 670
  

  67.0 x 10¹
  6.7 x 10² g/mL
  6.70 x 10² g/mL

• (b) 0.000006778
  

  6.77 x 10^-6
  0.678 x 10^-5
  6.78 x 10^-6

• (c) 4.35 x 10⁵ + 3.432 x 10⁴
  

  4.69 x 10⁵
  7.78 x 10⁵
  3.86 x 10⁴