Balanced equation: 2Fe + 3H2O → Fe2O3 +3H2
Convert g to mols:
285/55.845 = 5.1034 mols
Mole ratio of Iron and Iron (III) Oxide: 2:1
5.1034/2 = 2.5517 mols
You must first calculate the total weight of 1 mole of the substance. You do this by finding the molar weights on the periodic table of each of the elements in the compound:

So now we take the amount of each element that is given in the compound and divide it by the total mass of the compound:
Carbon: 96.08g

Carbon = 49.48%
Nitrogen: 56.028g

Nitrogen = 28.85%
Oxygen: 31.998g

Oxygen = 16.48%
Answer:
The bromine molecule, Br2 will likely react with Sr in a similar way to chlorine molecule, Cl2.
Explanation:
Chlorine belongs to group 7 of the periodic table. Elements in this group are known as halogens. Its molecule has the formula Cl2. The next element in the group after chlorine is bromine. Its molecule has a formula Br2. It has similar properties as chlorine, therefore, it would react with Strontium in a similar way to chlorine.
Elements belonging to the same group of the periodic the table have similar chemical properties as they contain the same number of valence electrons. Chlorine and Bromine both belong to group 7 of the periodic table and each have seven valence electrons. They both react with metals to form salts even though reaction with chlorine is more vigorous as it is more reactive than bromine. They both form negatively-charged ions with a charge of -1.
Reaction of Strontium with the halogens:
With chlorine: Sr + Cl2 ---> SrCl2
With bromine: Sr + Br2 ---> SrBr2
The salts formed are both crystalline salts with high melting and boiling points.
Answer:
636 mm Hg
Explanation:
The pressure in the gas container is equal to the atmospheric pressure minus the height of mercury:
Atmospheric pressure = 722 torr = 722 mm Hg
Height = 8.60 cm = 86 mm Hg
Pressure = 722 - 86 = 636 mm Hg
So none of the given options is correct, the correct answer is 636 mm Hg.
3+
So, compounds of boron contain boron in a positive oxidation state, generally +3. The sum of oxidation numbers of all constituent atoms of a given molecule or ion is equal to zero or the charge of the ion, respectively. ... In most of the stable compounds of boron, its oxidation number is +3