How many moles of nitrogen are in a 14.57 gram sample of nitrogen?

Explanation:

To convert from grams to moles, we must use the molar mass. This can be found on the Periodic Table. We have a sample of nitrogen, so look for N on the table.

Now, use this molar mass as a ratio.

Multiply by the number of grams in the sample (14.57)

Flip the fraction so the grams of nitrogen will cancel.

The original measurement of grams had 4 significant figures, so we need to round our answer to the same number of sig figs.

For the number we calculated, that is the thousandth place. The 1 in the ten thousandth place tells us to keep the 0 in the thousandth place.

There are about 1.040 moles of nitrogen in 14.57 grams.

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds