Find the number of bromine molecules present in 2.25 mol.

Answer is:  the number of bromine molecules is 1.35·10²⁴.

n(Br₂) = 2.25 mol; amount of bromine molecules.

Na = 6.022·10²³ mol⁻¹; Avogadro constant.

N(Br₂) = n(Br₂) · Na.

N(Br₂) = 2.25 mol · 6.022·10²³ mol⁻¹.

N(Br₂) = 13.54 ·10²³.

N(Br₂) = 1.35·10²⁴; number of bromine molecules.

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

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.