In a zero order reaction, it takes 342 seconds for 75% of a hypothetical reaction to decompose. Determine the half-life t1/2} in units of seconds. Do not enter units with your numerical answer.

Answer : The half-life is,

Explanation :

First we have to calculate the rate constant for zero order reaction.

The expression used is:

where,

= let initial concentration = 100

= final concentration = 25

t = time = 324 s

k = rate constant = ?

Now put all the given values in the above expression, we get:

Now we have to calculate the half-life.

The expression used is:

Thus, the half-life is,

they are both synthetic elements

explanation:

d

(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