That is a chemical change.. Hope I helped!
Answer: only Br2.
Justification.
In a chemical reaction the element that gains electrons experiments a reduction in its oxidation state, that is why it is said that it is reduced.
So, to know what element is being reduced you need to calculate the oxidation states of the elements involved.
Here I indicate the oxidation states of each element if the reaction putting them inside parenthesis:
Reactants side Products side
K (0) K (1+)
Br (0) Br(1-)
So, K lost one electron, increasing its oxidation statefrom 0 to 1+, meaning that it is being oxidized.
And, each atom of Br gained one electron, reducing its oxidation state from 0 to 1-, meaning it is being reduced.
Therefore, the answer is that Br2 is the substance being reduced.
<span>Active transport runs counter to facilitated diffusion. In active transport, molecules move against the concentration gradients, running from areas of lower concentration to areas of higher concentration. This is where energy is used.</span>
Molar mass:
Ag = 107.86 g/mol
Cu = 63.54 g/mol
Mole ratio:
Cu(s)+2 AgNO₃(aq)→Cu(NO₃)₂(aq)+2 Ag(s)
63.54 g Cu ------------- 2 x 107.86 g Ag
1.50 g Cu -------------- ??
Mass Ag = 1.50 x 2 x 107.86 / 63.54
Mass Ag = 32358 / 63.54
= 509.25 g of Ag
hope this helps!
The answer is the third choice because is oxidation half reactions, only the oxidation state of the reducing agent changes; in this third choice, Fe2+ is oxidized and becomes Fe3+. Just keep in mind that half reactions usually include the change in electrons:
Fe2+ -> Fe3+ +e-<span />
