How many hydrogen atoms are in 0.1488 g of phosphor
ic acid, H3PO4?

0.027×10²³ atoms of H

Explanation:

Given data:

Mass of phosphoric acid = 0.1488 g

Number of hydrogen atoms = ?

Solution:

First of all we will calculate the number of moles of H₃PO₄.

Number of moles = mass/molar mass

Number of moles = 0.1488 g/ 98 g/mol

Number of moles = 0.0015 mol

1 mole of H₃PO₄ contain = 3 mol of H

0.0015 mol× 3= 0.0045 mol

Now we will calculate the number H atoms.

1 mole = 6.022×10²³ atoms

0.0045 mol×6.022×10²³ atoms  / 1 mol

0.027×10²³ atoms of H

the answer is true.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.