What is the concentration of NO3- ions in a solution prepared by dissolving 20.0 g of Ca(NO3)2 in enough water to produce 300. mL of solution

0.812 M

Explanation:

The reaction that takes place is:

First we convert grams of Ca(NO₃)₂ to moles, using its molecular weight:

Then we convert Ca(NO₃)₂ moles to NO₃⁻, keeping in mind the stoichiometry of the reaction:

Finally we divide the number of moles by the volume (in L), to calculate the concentration:

(300.0 mL ⇒ 300.0 / 1000 = 0.300 L)

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