The given question tells you that a certain piece of wire has a mass  = 2.0 g per meter
That means that if you consider a piece of wire that is 1 m in length, its mass will be equal to  2.00 g .
According to question,
Now, you know that
1 m = 100 cm
Mass of  2.00 g  of copper will correspond to a wire that is a 100 cm long.
This implies that  0.28 gof copper will correspond to a wire that is
0.28 g * 100 cm /  2.0 g = 14 cm long
Hence, 14 cm of the wire would be needed to provide 0.28 g of copper.
Properties of Copper :
High conductivity and ductility.
Non magnetic.
To know more about Copper here:
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<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles. We do as follows:
4.50 mol Fe ( 6.022x10^23 atoms / 1 mol Fe ) = 2.71x10^24 atoms Fe present </span>
        
             
        
        
        
Answer:

Explanation:
You calculate the energy required to break all the bonds in the reactants.
Then you subtract the energy needed to break all the bonds in the products.
                              CH₃CH₂OH        +  3O₂ ⟶ 2CO₂ + 3H₂O
Bonds:         5C-H 1C-C 1C-O 1O-H    3O=O     4C=O   6O-H
D/kJ·mol⁻¹:    413    347  358  467       495        799      467
