How many atoms are in 356.13 grams of sn

There are three atoms of Sn (Stannous or Tin) in 356.13 g of Sn.

One atom of Sn has the atomic mass (mₐ) of 118,71u which means:

356.13/118.71=3 atoms of Sn

The mass number (symbol A) also called atomic mass number or nucleon number is the total number of protons and neutrons in an atomic nucleus. It determines the atomic mass of atoms and it is in the periodic table.

3 × 10⁴ kJ

Explanation:

Step 1: Write the balanced thermochemical equation

C₃H₈(g) + 5 O₂(g) ⟶ 3 CO₂(g) + 4 H₂O(g) ΔH = -2220 kJ

Step 2: Calculate the moles corresponding to 865.9 g of H₂O

The molar mass of H₂O is 18.02 g/mol.

865.9 g × 1 mol/18.02 g = 48.05 mol

Step 3: Calculate the heat produced when 48.05 moles of H₂O are produced

According to the thermochemical equation, 2220 kJ of heat are evolved when 4 moles of H₂O are produced.

48.05 mol × 2220 kJ/4 mol = 2.667 × 10⁴ kJ ≈ 3 × 10⁴ kJ