Scientific Notation的題目

1. If 58.5g of salt contains 6x10^23 molecules,find the weight of each molecule of salt.


the weight of each molecule of salt = 58.5 / 6x10^23
= 585 X 10^-1/6x10^23
= (585/6) x 10^(-1-23)
= 97.5 x 10^-24
= 9.75 x 10 x 10^-24
= 9.75 x 10^-23 g


2. The speed of light is 3x10^8 m/s. If a plane takes 253 hours to cover a distance equivalent to the distance that light travels in 1s,find the speed of the plane in km/h.



the travelling distance of the plane in m = 3 x 10^8 x 1 = 3 x 10^8 m

The speed of the plane = 3 x 10^8/253 m/hr
= 3 x 10^8/2.53 x 10^2 m/hr
= 1.186 x 10^6 m/hr
= 1.186 x 10^6 / 10^3 km/hr
= 1.186 x 10^(6-3)
= 1.186 x 10^3 km/hr

1. If 58.5g of salt contains 6x1023 molecules,find the weight of each molecule of salt.

the weight of each molecule of salt = 58.5 / 6x1023
= 9.75 x 10-23


1. The speed of light is 3x108 m/s. If a plane takes 253 hours to cover a distance equivalent to the distance that light travels in 1s,find the speed of the plane in km/h.


the speed of the plane in km/h = 300000 / 253 = 1190 km/h