Calculate the atoms of hydrogen in 52.0 g of H2O.

34.81 ×10²³ atoms

Explanation:

Given data:

Mass of water = 52.0 g

Number of atoms of hydrogen = ?

Solution:

Number of moles of water:

Number of moles = mass/molar mass

Number of moles = 52.0 g/ 18 g/mol

Number of moles = 2.89 mol

1 mole of water contain 2 mole of hydrogen.

2.89 mole of water contain 2.89× 2= 5.78 moles of hydrogen.

Number of atoms of hydrogen:

1 mole = 6.022×10²³ atoms

5.78 mol ×  6.022×10²³ atoms / 1mol

34.81 ×10²³ atoms

the answers would be

the first one and the second one

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.