Which expression gives the mass percent of carbon in methanoic (formic) acid, hcooh?

12/29 x 100
12/46 x 100
2/46 x 100
16/46 x 100

12/46 * 100

Explanation:

To solve this problem, the atomic masses of the individual elements present in the mix must be taken into consideration.

The atomic mass of carbon is usually 12 a.m.u , the atomic mass of hydrogen is 1 a.m.u while the atomic mass of oxygen is 16 a.m.u

These are the three elements present in methanoic acid. Now, we can calculate the molar mass of the acid.

This is : 1 + 12 + 2(16) + 1 = 46g/mol

Now, to express the percentage of the carbon present, we simply place the atomic mass of the carbon over the total mass and multiply by 100. This is thus 12/46 * 100

the answer to your question is c.

if you read the house of usher you should know that the house was haunted

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.