The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
Answer:
Sublimation is a phase transition that occurs when a solid changes into a gas — or, as
Explanation:
Answer:
The change in internal energy of the heater is 0 kJ
Explanation:
∆U = Q - W
Q is quantity of heat transferred = 1 kJ
W is work done on the heater = 1 kJ
Change in internal energy (∆U) = 1 - 1 = 0 kJ
Answer:
Inverse proportion occurs when one value increases and the other decreases. For example, more workers on a job would reduce the time to complete the task. They are inversely proportional.
Answer:
Mass of lava is 8370 g.
Explanation:
Density:
Density is equal to the mass of substance divided by its volume.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
Symbol:
The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.
Given data:
density of lava = 3.1 g/cm³
volume= 2700 cm³
mass= ?
Solution:
d = m/v
m = d×v
m = 3.1 g/cm³×2700 cm³
m = 8370 g
