Element: Boron
Symbol: B
So answer is B
Answer:
the mass of the air in the room is 4.96512 kg ( in 0°C)
Weight percentage of nitrogen can be calculated using the following rule:
weight percentage of nitrogen = (weight of nitrogen / weight of urea) x 100
From the periodic table:
molecular mass of carbon = 12 grams
molecular mass of nitrogen = 14 grams
molecular mass of hydrogen = 1 grams
molecular mass of oxygen = 16 grams
therefore:
mass of nitrogen in urea = 2(14) = 28 grams
mass of urea = 12 + 2(14) + 4(1) + 16 = 60 grams
Substitute with the masses in the equation to get the percentage:
weight percentage of nitrogen = (28/60) x 100 = 46.667%
Hello! Your answer is C, one atom of iron and three atoms of chlorine.
In this case, there is some ambiguity with "Cl". It could be C + I, or Cl. (One being carbon + iodine and the other Chlorine). However, we can see that the only choice that mentions iodine states two atoms, which is incorrect, as if it was iodine, the 3 indicates that there would be three atoms.
Therefore, Cl must be chlorine. If you look at choice C, there are three atoms of chlorine, as indicated by the 3 at the end of the Cl. There is also one molecule of Fe, as there is no number at the end of it so there has to be only one.
B is not correct, as carbon would be only "C". A is not correct as a molecule is a collection of atoms bonded together, therefore, this compound could be named a molecule, but there are not multiple molecules inside this compound.
Hope this helps!
1. Elements are composed of atoms that are indestructible
2. All atoms of a given element are identical; same size/mass/chemical properties
3. Atoms of 1 element are different from the atoms of other elements
4. Compounds are composed of atoms with more than 1 element. The relative number of atoms for each element are of a given compound are always going to be the same.
(Extra one) 5. Chemical reactions are only ever going involve the rearrangement of the atoms. Atoms are not created/destroyed during the chemical reactions. (Law of Conservation of Mass: nothing can ever be created or destroyed.)