In an experiment, a 2.514-g sample of calcium was heated in a stream of pure
oxygen, and was found to increase in mass by 1.004 g. calculate the empirical
formula of calcium oxide.

CaO.

Explanation:

The mass of Calcium is 2.514 g .and of oxygen is 1.004 g.

Dividing by their molar masses:

2.514 / 40.078 =  0.06273

1.004 / 15.999 = 0.06275

- the ratio of Ca to O is  very close to 1:1 so the empirical formula is CaO.

(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