An electric motor produces heat while running. The amount of heat is roughly equivalent to the amount of power delivered to the motor.
Answer: d. Water is the most abundant atom in Earth’s atmosphere.
Explanation:
Water percentage in the atmosphere is 0.001 percent only as it not the major reservoir or source of water. The water is available in the atmosphere in the form of water vapors. These water vapors when aggregate and their concentration becomes high they fall down as rain on earth so the rain is collected in water reservoirs like oceans, rivers, lakes, ponds, aquifers, and other sources of water, which are the components of hydrosphere on earth. So, hydrosphere is most abundant in water. Moreover, water is not an atom instead it is the molecule formed by the combination of two molecules of hydrogen and one molecule of oxygen.
Answer: 448 g of 
will be required to completely react with 784g moles of CO(g) during this reaction.
Explanation:
To calculate the moles :
The balanced chemical equation is:
According to stoichiometry :
2 moles of 
require = 1 mole of
Thus 28 moles of will require=
of
Mass of 
Thus 448g of will be required to completely react with 784g moles of CO(g) during this reaction.
Tell you what - the more likely scenario is that iron reacts with oxygen to form 6.2g of Fe2O3. That's the rusting of iron; I don't know if you can "un-rust" iron back into pure iron and oxygen. So we'll go with this equation:
4Fe + 3O2 --> 2Fe2O3.
Iron (Fe) is our unknown. Okay, Fe2O3, which is iron(III) oxide, has a given mass of 6.2g, and according to the Periodic Table, it's molar mass, or grams per 1 mole, is 160g/mol (56+56+16+16+16). Do a 1-step molar conversion to get about 0.03875 moles. Apply this to the molar ratio of coefficients in the balanced equation: the ratio is 2:4, or 1:2, so you will double that to 0.0775 moles of iron. Now do a 1-step molar conversion with iron's Atomic Mass to get your grams of iron: 0.0775 moles x 56 grams per mole = 4.34 grams Fe.
