The balanced chemical reaction would be
<span>4Fe(s) + 3O2(g) ---> 2Fe2O3(s)
We are given the amount of Fe to be used in the reaction. We use this as the starting point for the calculations. We do as follows:
25.9 g Fe (1 mol / 55.85 g) ( 2 mol Fe2O3 / 1 mol Fe ) (159.69 g / mol ) = 262.48 g Fe2O3 produced</span>
The uncertainties of the delta measurements and the uncertainty of the atomic weight derivedfrom the best measurement of isotopic abundances constrain the number of significant figures in theatomic-weight values of the upper and lower bounds. For carbon, the fifth digit after the decimal pointis uncertain because of the uncertainty value of 0.000 027. Therefore, the number of significant digitsin the atomic-weight value is reduced to four figures after the decimal point. The Commission may rec-ommend additional conservatism and reduce the number of significant figures further. For the lowerbound of carbon, 12.009 635 is truncated to 12.0096. For an upper bound, the trailing digit is increasedto ensure the atomic-weight interval encompasses the atomic-weight values of all normal materials. Inthe case of carbon, the upper bound is adjusted from 12.011 532 to 12.0116 to express four digits afterthe decimal point. The lower and upper bounds are evaluated so that the number of significant digits ineach is identical. If a value ends with a zero, it may need to be included in the value to express therequired number of digits. The following are examples of lower and upper atomic-weight bounds foroxygen that could be published by the Commission in its various tables.
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Extracted from" Atomic weights of the elements 2009 (IUPAC Technical Report)"
I think the correct answer is option 3. CaCl2 is the compound that is an electrolyte when dissolved in water. An electrolyte is a substance that conducts electricity in solution. Calcium Chloride when in solution dissociates into ions which allows the flow of current in the solution.
Answer:
Examples of Chemical Changes
Burning wood.
Souring milk.
Mixing acid and base.
Digesting food.
Cooking an egg.
Heating sugar to form caramel.
Baking a cake.
Rusting of iron.