A control group is the comparison group that helps to "make sure your experiment works." A control group is separated from the rest of the experiment and nothing happens to it kinda like a controlled variable. Controlled variables are the variables in a experiment that remains the same for example a temperature, time, type of products, etc..
Hope this helps!
Answer:
Hello your question is poorly written below is the well written question
Uranium, an important component of both nuclear weapons and nuclear reactors, has two major isotopes, U-238, which has a half-life of approximately 4.5 billion years, and U-235, which has a half-life of approximately 700 million years. Both were present in equal amounts at the time of the creation of the Earth, 4.5 billion years ago. How many years after the creation of the Earth had the amount of radiation from uranium decayed to half the amount present at the time of the creation of the Earth
Answer : 140 billion years
Explanation:
Given that :
U-238 h1/2 = 4.5 billion years
U-235 h1/2 = 700 million years
At the beginning both Isotopes where present in equal amount
Determine the T years before the amount of Uranium decays to Half
T = ? N'2 = N1 / 2
we know that N = No ( 1/2 )^h where h = time / half-life time
attached below is the detailed solution of the given problem
Answer:
The Avogadro's number is 
Explanation:
From the question we are told that
The edge length is 
The density of the metal is 
The molar mass of Ba is 
Generally the volume of a unit cell is

substituting value
![V = [5.02 *10^{-10}]^3](https://tex.z-dn.net/?f=V%20%3D%20%20%5B5.02%20%2A10%5E%7B-10%7D%5D%5E3)
From the question we are told that 68% of the unit cell is occupied by Ba atoms and that the structure is a metal which implies that the crystalline structure will be (BCC),
The volume of barium atom is

substituting value


The Molar mass of barium is mathematically represented as

Where
is the Avogadro's number
So

substituting value


Answer:
5.004kg
Explanation:
Combustion of carbon
C+O2=CO2
from the relationship of molar ratio
mass of carbon/molar mass of carbon=volume of CO2 produced\molar vol(22.4 dm3)
mass of carbon =1000kg
atomic mass of carbon =12
volume of CO2 produced=1000×22.4/12
volume of CO2 produced =1866.6dm3
from the combustion reaction equation provided
CO2 (g) + 2NH3 (g) ⟶ CO (NH2 )2 (s) + H2 O(l)
applying the same relationship of molar ratio
no of mole of CO2=no of mole of urea
therefore
vol of CO2\22.4=mass of urea/molar mass of urea
molar mass of urea=60.06g/mol
from the first calculation
vol of CO2=1866.6dm3
mass of urea=1866.6×60.06/22.4
mass of urea=5004.82kg
When an atom combines chemically with another atom, it either gains, loses, or shares ELECTRONS.