1. how many atoms are there in 1.7 mol ca?

There are atoms in 1.7 mol Ca

Solution:

Initially we have to convert the given mass of calcium to moles of calcium, using its molar mass (referring to a periodic table, this is 40.08  g/mol

Using Avogadro's number, as

We can calculate the number of atoms present by

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.

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