If we measure the HEIGHT of all the students in our class with a ruler (only accurate to the nearest whole number) and use a calculator to get an average, we get an answer of 172.3421 centimeters.

We cannot claim that level of accuracy.

How do we write our final answer for average height?

Significant Figure rules are never applied to "Exact Values".

If you borrow, $15,000 from the bank for a car, it must be exactly $15,000 (not $10,000 or $14,821). This means all 5 digits are significant.

The Speed Limit on a road is also an "Exact Value".

If the speed limit on the Autobahn in Germany is 130 kilometer per hour, how many significant figures are there?

Do you remember scientific notation? Sometimes it can help figure out the number of Significant Figures, rather than use all of the rules.

The distance between the Earth and the moon is 382,500,000 meters. How do you write this in scientific notation?

• 3825x10⁵

• 382.5x10⁶

• 38.25x10⁷

• 3.825x10⁸

Do you remember scientific notation? Sometimes it can help figure out the number of Significant Figures, rather than use all of the rules.

The distance between the Earth and the moon is 382,500,000 meters. You have now written this in scientific notation.

How many Significant Figures are in this number?

Do you remember scientific notation? Sometimes it can help figure out the number of Significant Figures, rather than use all of the rules.

The distance between Silicon atoms in a Silicon Crystal is 0.000000000235 meters. How do you write this in scientific notation?

• 2350x10^-13

• 2.35x10^-10

• 23.5x10^-11

• 235x10^-12

Do you remember scientific notation? Sometimes it can help figure out the number of Significant Figures, rather than use all of the rules.

The distance between Silicon atoms in a Silicon Crystal is 0.000000000235 meters. You have now written this in scientific notation.

How many Significant Figures are in this number?

2 mol of hydrochloric acid (HCl) is dissolved into 220.0 g of water. Find the total weight of the HCl solution.

1 mol of HCl is 36.46 g/mol

What is the weight with the correct number of significant figures?

Tags

NGSS.MS-PS1-5

In addition and subtraction, the significant figures in the answer must reflect the

• average number of significant figures in the problem.

• number in the calculation with the most significant figures.

• number in the calculation with the fewest significant figures.

• least precise measurement in the calculator (i.e. least number of decimal places)

In division and multiplication, the answer must not have more significant figures than the

• average number of significant figures in the problem.

• least precise measurement in the calculation (i.e. least number of decimal places)

• number in the calculation with the fewest significant figures.

• number in the calculator with the most significant figures.

Which of the following numbers contains the designated CORRECT number of significant figures?

• 1.02 - 2 significant figures

• 168000 - 3 significant figures

• 0.00802 - 2 significant figures

• 0.02300 - 5 significant figures

• 3.0450 - 4 significant figures