You have to calculate the oxidation estates of the atoms in each compound.
I will start with K2Cr2O7 because I believe that Cr is the best candidate to reduce its oxidation number in 3 units.
In K2Cr2O7:
- K has oxidation state of 1+, then K2 has a charge of 2* (1+) = 2+.
- O has oxidation state of 2*, then O7 has a charge of 7* (2-) = 14-.
That makes that Cr2 has charge of 14 - 2 = +12, so each Cr has +12/2 = +6 oxidation state.
In Cr2O3:
- O has oxidation state of 2-, then O3 has charge 3 * (2-) = - 6
- Then, Cr2 has charge 6+, and each Cr has charge 6+ / 2 = 3+.
So, we have seen that Cr reduced its oxidation state in 3 units, from 6+ to 3+.
Answer: Cr has a change in oxidation number of - 3.
Answer:
Mw = 179.845 g/mol
Explanation:
∴ w = 26.2 g
∴ 1 mol = 6.02 E23 molecules.......Avogadro's number
⇒N° moles = 8.77 E22 molecules * ( mol / 6.02 E23 molecules ) = 0.146 mol
⇒ Mw = 26.2 g / 0.146 mol = 179.845 g/mol
What effect does removing predators have on prey?
:It means that as they are removed the predators go hungry and they could become extinct.
Hope I helped!
<u>Answer:</u>
<em>4.5 L water we have in litres (L).</em>
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<u>Explanation:</u>

where
= Final T - Initial T
Q is the heat energy in calories
c is the specific heat capacity (for water 1.0 cal/(g℃))
m is the mass of water
Plugging in the values

So,
Volume of water = mass/density

=4.5 L (Answer)