Given the heat change per mole for the combustion of methanol (-726 kJ/mol), predict the heat change that would occur if 0.200 mol of methanol undergoes the same reaction

-145.2kJ

Explanation:

Enthalpy is an extensive property as its value depends on the amount of substance present in the system.

If the enthalpy for one mole of methanol = -726 kJ/mol;

The Enthalpy for 0.2 mol is given as;

Enthalpy = 0.200 * 726

Enthalpy = -145.2kJ

It would take -145.2kJ for 0.200 mol of methanol to undego the combustion reaction.

(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