The type of reaction of Fe2O3 + 2SiO2 → Fe2Si2O7 would be that it is a synthesis reaction. It is a type of chemical reaction in which two or more simple substances combine to form a more complex product. Hope this answers the question.
Answer:
A. The cost of producing a kilowatt of power with fuel cell will be less than $30 in 2015
Answer: The mass of electrons is mostly ignored because electrons are extremely small compared to neutrons and protons.
Explanation: A proton is about 1,836 times the size of an electron.
On the periodic table, the atomic number for each element can be found. This number is found by measuring the weight of 6.02 x 10^23 atoms of the element in grams. Electrons aren't ignored when finding exact math, but for the sake of simplification high school teachers will generally have you only count the number of protons and neutrons when calculating the mass of atoms.
I’d say A. They are theoretical in the fact that they have not been observed directly, but have been confirmed to exist through experimentation.