Answer:
21. Erosion causes physical changes. For example - Land degradation, deforestation.
20. B statement is closely related to climate.
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Answer:
1.204428 * 10^24 atoms
Explanation:
Number of moles = 2 mol
Number of atoms = ?
The relationship between moles and atoms is given by the avogadro's umber. This is the number of units in one mole of a substance. The units can be atoms, ions etc In this case it is atoms. The number is equal to 6.02214076 * 10^23
This means;
1 mol = 6.02214076 * 10^23
2 mol = x
Upon solving for x,
x = 2 * 6.02214076 * 10^23
x = 12.04428 * 10^23
x = 1.204428 * 10^24 atoms
The amount of current required to produce 75. 8 g of iron metal from a solution of aqueous iron (iii)chloride in 6. 75 hours is 168.4A.
The amount of Current required to deposit a metal can be find out by using The Law of Equivalence. It states that the number of gram equivalents of each reactant and product is equal in a given reaction.
It can be found using the formula,
m = Z I t
where, m = mass of metal deposited = 75.8g
Z = Equivalent mass / 96500 = 18.6 / 96500 = 0.0001
I is the current passed
t is the time taken = 75hour = 75 × 60 = 4500s
On subsituting in above formula,
75.8 = E I t / F
⇒ 75.8 = 0.0001 × I × 4500
⇒ I = 168.4 Ampere (A)
Hence, amount of current required to deposit a metal is 168.4A.
Learn more about Law of Equivalence here, brainly.com/question/13104984
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Answer:
a)22.2°C after adding magnesium
b)17.3°C before adding magnesium
c) 4.9 is change
Because they have similar attractive forces in their molecules
