The radius of a aluminum atom is 143 pm. How many aluminum atoms would have to be laid side by side to span a distance of 2.36 mm?

1.65x10⁷ atoms of Al have to be laid side by side to span a distance of 2.36mm

Explanation:

We can assume Aluminium atoms as balls ordered side by side. As the radius of 1 atom is 143pm = 143x10⁻¹²m, the space that 1 atom occupies is 2 radius = 286x10⁻¹²m. That means to occupy 2.36mm = 2.36x10⁻³ you require:

2.36x10⁻³m ₓ ( 1 atom Al / 143x10⁻¹²m) =

its mg hope this

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.