<span>sunspots, hope this helps!!!!</span>
To calculate moles from grams using chemical formulas ... However, one mole of magnesium weighs 24.31 g. ... 0.873 g x 95.21 g = 9.17 x 10-3 mol MgCl2.
Answer:
B) 8.0 molecules.
Explanation:
- From the balanced equation: <em>3Cu + 8HNO₃ → 3Cu(NO₃)₂ + 2NO + 4H₂O,</em>
It is clear that 3.0 atoms of Cu react with 8.0 molecules of HNO₃ to produce 3.0 molecules of Cu(NO₃)₂, 2.0 molecules of NO, and 4.0 atoms of H₂O.
<u><em>Note that: </em></u>The no. of atoms and molecules is the same ratio to the no. of moles.
<u><em>Using cross multiplication:</em></u>
3.0 atoms of Cu produce → 2.0 molecules of NO, from the balanced equation.
12.0 atoms of Cu produce → <em>??? molecules of NO.</em>
<em>∴ The no. of molecules of NO produced </em>= (2.0 molecules)(12.0 atoms)/(3.0 atoms) = <em>8.0 molecules.</em>
Answer:
5. +5
6. +7
Explanation:
The oxidation state can be obtained as follow:
5. Oxidation state of oxygen, O = –2
Oxidation state of phosphorus, P =?
P3O10 = –5
3P + 10O = –5
3P + (10 x –2) = –5
3P – 20 = –5
Collect like terms
3P = –5 + 20
3P = 15
Divide both side by 3
P = 15/3
P = +5
Therefore, the oxidation state of P in P3O10^5- is +5
6. Oxidation state of oxygen, O = –2
Oxidation state of manganese, Mn =.?
Mn2O7 = 0
2Mn + 7O = 0
2Mn + (7 x –2) = 0
2Mn – 14 = 0
Collect like terms
2Mn = 14
Divide both side by 2
Mn = 14/2
Mn = +7
Therefore, the oxidation state of Mn in Mn2O7 is +7
