Chem Unit 1: Uncertainty in Measurements

For which of these numbers would you need to considered significant figures? (Check all that apply)

• You used the conversion factor

  1 mile = 1.62 km

• You counted 22 students in a classroom.

• You measured a rock to be 34.5g.

• You calculated the density of an object to be 7.8 g/mL.

Tags

NGSS.HS-PS3-1

You calculated the density of calcium carbonate to be 3.1 g/mL. A trusted source lists it as 2.7 g/mL. Calculate the percent error in your measurement.

• 0.4%

• 15%

• 13%

• 5.8%

How many sig figs does this number have?

0.01050

• 3

• 4

• 5

• 6

How many sig figs does this number have?

72,000

• 3

• 4

• 5

• 2

How many sig figs does this number have?

8.3 x 10⁹

• 3

• 4

• 5

• 2

Express 5,048,941

in scientific notation rounded to 3 sig figs.

• 5.05 x 10⁶

• 5.05 x 10^-6

• 5.049 x 10⁶

• 505

Express 0.000 007 439

in scientific notation rounded to 2 sig figs.

• 7.4 x 10⁶

• 7.4 x 10^-6

• 7.439 x 10^-6

• 74

Express 219.51

in scientific notation rounded to 2 sig figs.

• 2.2 x 10²

• 2.2 x 10^-2

• 22

• 2.1951 x 10²

Solve and round to the appropriate sig figs.

412.32 + 39

• 451.32

• 451

• 451.3

• 500

Solve and round to the appropriate sig figs.

57.1 - 0.88

• 56.22

• 56.2

• 56

• 60