Answer:
Number of moles = mass/molar mass
Explanation:
Given data:
mass of Al = 11 g
Moles = ?
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of aluminium is 27 g/mol
Now we will put the values in formula.
Number of moles = 11 g/ 27 g/mol
Number of moles = 0.41
The number of moles in 11 g Al are 0.41 mol.
Answer:
<u> </u><u>85.952 ml</u> 
needed to titrate the excess complexing reagent .
Explanation:
Lets calculate
After addition of 80 ml of EDTA the solution becomes = 20 + 70 = 90 ml
As the number of moles of 
=
=
=0.01172
Molarity = 
=
=0.000586 moles
Excess of EDTA = concentration of EDTA - concentration of CoSO4
= 0.009005 - 0.000586
= 0.008419 M
As M1V1 ( Excess of EDTA ) = M2V2 
V2 =85.952 ml
Therefore , <u>85.952 ml </u> needed to titrate the excess complexing reagent .
Answer:
1/4 or 25%
Explanation:
The Arctic region of the earth refers to that part of the earth around the north pole region. Hence, when we are talking about latitude O degrees North, the areas around this geographical location is referred to as the arctic.
Now , there is an estimated 1/4 or 25% of the world’s oil and natural gas here. Unfortunately, these are yet accessible because of the amount of ice or snow covering. With increase in technological advancements, this might be accessible in the nearest future
<span>This problem is not about chemistry it is about math. the half-life of a certain thing is the time that it needs to decay 50% of what it had before. so if there is 4g, after 1 half there will be only 2g. so to become 1g it is passed 2 half-lives. 4,0g, 2,0g, 1,0g so it is the time divided by 2( numbers of half-lives). So the half-life of Francium 210 is 2,6 min.</span>
