Answer:
25 grams
Explanation:
You strat off with 400 grams of your substance. By day 14, half has dcayed and you only have 200 grams left. By day 28, there are 100 grams of the substance. On day 42, there are 50 grams left. Finally, on day 56, the substance has been through four half-lives and 25 grams remain.
You can start by writing out the molecular formula of each molecule.
Aluminum (Al 3+) Phosphate (PO4 3-)
AlPO4
Nickel II (Ni 2+) sulfide (S 2-)
NiS
Aluminum Sulfide
Al2S3
Nickel Phosphate
Ni3(PO4)2
If you’re wondering, we get those charges by looking at the periodic table. The metals usually have a + charge based on their group number. The nonmetals usually - charge egual to 8 - their group number.
You then balance the ions by flipping the charges, dropping the signs, and adding them in as subscripts.
Now we can put it into an equation
AlPO4 + NiS —-> Al2S3 + Ni3(PO4)2
Balance by adding coefficients
2 AlPO4 + 3 NiS —-> Al2S3 + Ni3(PO4)2
For part 1, just copy them off of the periodic table. For example, element 1 is Hydrogen, and its symbol is H
Elements on the left usually lose electrons and elements on the right tend to gain them. Noble gases have no charge.
If the standard reduction potential of a half-cell is positive, the reduction reaction is spontaneous when paired with a hydrogen electrode
<u>Explanation:</u>
- The relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell.
- If the standard reduction potential of a half-cell is positive, the reduction reaction is spontaneous when paired with a hydrogen electrode.
- The reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.
- The reduction to happen the electrons gained by the material that is being decreased must be transported from the atoms of ions of a different material.