What is the mass of 5.2 x 10^21 atoms of Vanadium?

Mass = 0.44 g

Explanation:

Given data:

Mass of vanadium =  ?

Number of atoms of vanadium = 5.2 × 10²¹ atoms

Solution:

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

5.2 × 10²¹ atoms ×  1mol / 6.022 × 10²³ atoms

0.86× 10⁻²  mol

0.0086 mol

Mass of vanadium:

Mass =  number of moles × molar mass

Mass = 0.0086 mol × 50.9 g/mol

Mass = 0.44 g

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option c: 1605.1 kj

the balanced chemical reaction for combustion of methane is as follows:

here, enthalpy formation of is -74.7 kj/mol, 0 kj/mol, -393.5 kj/mol and -241.82 kj/mol respectively.

the heat released or can be calculated as follow:

putting the values,

thus, heat released by combustion of 1 mol of methane is 802.54 kj/mol. thus, for 2 mol, heat released will be:

therefore, heat released by the combustion of 2 mol of methane is 1605.1 kj.