Question

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Answer 1

Answer:

Explanation:

The first one is CrO.  The Chromium has the same charge as the oxygen so mol numbers are dropped.

The Second one is CrO2 The two oxygens have a charge of 2(-2) = -4. To balance this, the Chromium must have a charge of +4 Cr(Iv)O2

The third one is can be set up like this

Cr + 3(-2) = 0

Cr - 6 = 0

Cr = 6

Therefore the formula is Cr(vi)O3

The last one is a bit tricky. Follow this carefully. There are 2 Crs and 3Os.

The formula looks like this

2Cr + 3(-2) = 0

2Cr - 6 = 0

2Cr = 6

Cr = 3

The formula is Cr(iii)2 O3