Over the first 57.0 s of the reaction the concentration of hydrogen (H2) dropped from 1.50 M to 0.323 M. Calculate the average change in concentration of ammonia (∆NH3/ ∆t) , in M/s, over this time interval?

0.021M/s

Explanation:

Rate Average = |ΔConcentration / Δtime| = | Δ[NH₃]/Δt |

=  | 0.323M - 1.50M / 57.0s | = | -0.021M/s | = 0.021M/s

Note: calculation of average rate of reaction should be represented as a positive value representing 'speed' of reaction. Many will argue that speed, or rate can be negative (-), but speed is a scalar quantity that represents change of position over a period of time. Acceleration can be negative (~deceleration) but speed is absolute. For example, if one is moving at a speed of 30mi/hr then its is 30mph or it is not 30mph, but can not be a negative in the context of rate.   If you bring this up, you will be challenged. Good Luck :-)

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied