First, we divide the number of atoms of silicon given in the problem above by Avogadro's number 6.6022 x10^23. This will give us the number of moles of silicon. Then, we multiply the number of moles by the molar mass of silicon.
number of moles = (3.6 x 10^20 atoms/6.022x10^23 atoms) = 5.97x10^-4 moles
Then, multiplying by the molar mass
(5.97x10^-4 moles)(28.0855 g/mol) = 0.017 grams

4 0

3 years ago

Explain whether hydrogen bonding is present between hydrogen<br><br> fluoride (HF) molecules

Mamont248 [21]

Hydrogen bonding occurs when hydrogen is bonded to an oxygen or nitrogen or fluorine atom. In this case, the hydrogen atom in a hydrogen fluoride molecule will be able to bond to the fluoride atom of another hydrogen fluoride molecule, forming a hydrogen bond.

6 0

2 years ago

Use the following information to answer the next two questions:......Aqueous lithium chloride, liquid dihydrogen monooxide, and

mestny [16]

Answer:

Explanation:

7 0

3 years ago

In 1987 the first substance to act as a superconductor at a temperature above that of liquid nitrogen (77 k) was discovered. the

Mila [183]

The molar mass of the elements are:

Yttrium (Y) = 88.91 g / mol

Barium (Ba) = 137.33 g / mol

Copper (Cu) = 63.55 g / mol

Oxygen (O) = 16 g / mol

Calculating for the molar mass of YBa2Cu3O7:

YBa2Cu3O7 = 88.91 + 2(137.33) + 3(63.55) + 7(16) = 666.22 g / mol

The masses of the elements in 1 mole of YBa2Cu3O7 are:

Yttrium (Y) = 88.91 g / mol (1 mole) = 88.91 g

Barium (Ba) = 137.33 g / mol (2 mole) = 274.66 g

Copper (Cu) = 63.55 g / mol (3 mole) = 190.65 g

Oxygen (O) = 16 g / mol (7 mole) = 112 g

We now calculate for the percent composition by mass of each element:

% Y = 88.91 g / 666.22 g = 13.35%

% Ba = 274.66 g / 666.22 g = 41.23%

%Cu = 190.65 g / 666.22 g = 28.62%

3 0

3 years ago