In order to find out the %mass dolomite in the soil,
calculate for the mass of dolomite using the information given from the
titration procedure. You would need to multiply 57.85 ml with 0.3315 M HCl and
you would get the amount of HCl in millimoles. Then multiply the amount of HCl
with 1/2 (given that for every 1 mol of dolomite, 2 mol of HCl would be
needed). Convert the amount of dolomite to mass by multiplying the millimoles
with the molecular weight which is 184.399. Then convert the mass to grams
which is 1.768 grams. Divide the mass of dolomite (1.768 grams) with the weight
of soil sample. The % mass is 7.17.
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Answer : The correct option is, (C) 6
Explanation :
Oxidation-reduction reaction : It is a reaction in which oxidation and reduction reaction occur simultaneously.
Oxidation reaction : It is the reaction in which a substance looses its electrons. In this oxidation state increases.
Reduction reaction : It is the reaction in which a substance gains electrons. In this oxidation state decreases.
The given unbalanced chemical reaction is,
Half reactions of oxidation and reduction are :
Oxidation : 
......(1)
Reduction : 
.......(2)
In order to balance the electrons, we multiply equation 1 by 2 and equation 2 by 3, we get:
Oxidation : 
......(1)
Reduction : 
.......(2)
The overall balanced chemical reaction will be:
From this reaction we conclude that the electrons are getting transferred from iron to iodine and the number of electrons transferred are 6 electrons.
Hence, the correct option is, (C) 6
Answer:
36290 min = 604.8 hr.
Explanation:
1 lbs = 453.59237 grams.
∴ 2 lbs = 907.18474 grams.
<em><u>Using cross multiplication:</u></em>
500 mg of iron oxide dissolved → 20 minutes.
907184.74 mg of iron oxide dissolved → ??? minutes.
<em>∴ The time needed to dissolve 2 lbs of iron oxide =</em> (907184.74 mg)(20 min)/(500 mg) = <em>36290 min = 604.8 hr.</em>
