T=20 min
m₀=200 g
t=60 min
the mass of element through time t is:
m=m₀*2^(-t/T)
m=200*2^(-60/20)=25 g
25 grams of element will be left after 60 minutes
Answer:
The noble gases with complete outermost shell electrons.
Explanation:
Noble gases or inert gases do not react chemically with other elements because they have a complete configuration of their electronic shells. What drives chemical reaction is simply the exchange of electrons between two or more atoms. It can be a loss, a gain or simple sharing of electrons in order to achieve a complete configuration just like those of noble gases.
Answer:
2
Explanation:
Mass of water molecule = mass of hydrated salt - mass of anhydrous salt
Mass of water molecule = 5.00 - 4.26 = 0.74g of water molecule.
Number of moles = mass / molarmass
Molar mass of water = 18.015g/mol
No. of moles of water = 0.74 / 18.015 = 0.0411 moles.
Mass of BaCl2 present =?
1 mole of BaCl2 = 208.23 g
X mole of BaCl2 = 4.26 g
X = (4.26 * 1) / 208.23
X = 0.020
0.020 moles is present in 4.26g of BaCl2
Mole ratio between water and BaCl2 =
0.0411 / 0.020 = 2
Therefore 2 molecules of water is present the hydrated salt.
Answer: percentage of the copper recovered is 88.8 %
Explanation:
Given : Initial amount of copper = 0.502 g
Recovered amount of copper = 0.446 g
percentage of copper recovered = 
Putting in the values :
percentage of copper recovered = 
Thus percentage of the copper recovered is 88.8 %
