To get the weight of the body fat, you multiply the percentage of body fat (as a decimal) by the total body fat:
133x0.115=19.95
The athlete's body contains 19.95 pounds of fat.
molar mass Mg = 24 g/mol ; MgF2 = 62 g/mol
<span>Mg + 2 NaF = MgF2 + 2 Na
</span>
24 g Mg ------------ 62 g MgF2
5.50 g Mg ---------- ( mass MgF2)
mass MgF2 = 5.50 x 62 / 24
mass mgF2 = 341 / 24
= 14.208 g of MgF2
hoope this helps!
As a general rule of thumb molecules where metals interact with non-metals tend to form ionic bonds (because they form oppositely-charged ions), while molecules where non-metals interact with non-metals tend to form covalent bonds (because they share electrons to fill valence shells). Some of the options listed refer to large polymers of more basic units - if you can identify the basic units, you can get a sense of the kinds of bonds you're dealing with.
Starch is a polymer of glucose. Glucose is an organic molecule made of C, H, and O (all non-metals). It contains COVALENT bonds.
Graphite is a carbon polymer (sort of). Carbon is a non-metal. It contains COVALENT bonds.
Paraffin wax is a mixture of long-chain hydrocarbons (lots of carbons stuck together with some hydrogens stuck around the edges). Non-metals again. COVALENT.
Copper nitrate is a metal (copper) and a non-metal (the polyatomic ion nitrate, NO3-). Therefore, copper nitrate as a whole is IONIC (be careful though - the N and O within the nitrate ion are both non-metals and so are bonded covalently, but they ultimately form an ion that is capable of forming ionic bonds with metals).
Iron oxide is a general term for some combination of iron (a metal) and oxygen (a non-metal). Regardless of the specific combination, the interaction is IONIC.
Sucrose is formed when glucose interacts with another sugar, fructose. Again, only C, H, and O are involved, so the molecule is COVALENT.
Calcium carbonate is similar to the copper nitrate situation - you have a metal (calcium) and a non-metal (carbonate) interacting though an IONIC bond. As with nitrate, carbonate (CO3[2-]) is itself a polyatomic anion containing covalent bonds between the C and O's, but forms ionic bonds because it is ultimately an ion.
Happy to clarify anything if need be!
If you mean STEM, S is science, T is technology, and M is math.