The mass of an oxygen–18 atom is 18.0042 amu. Compute the calculated mass.

The calculated mass of one atom of oxygen-18  is approximately  2.99×10⁻²³ grams

Explanation:

The given mass of an oxygen-18 atom = 18.0042 amu

The definition of the atomic mass unit is the mass equivalent to the mass of one twelfth the atomic mass of one atom of carbon-12. The atomic mass unit is used to express the mass of an isotope of an element

1 amu = 1.66 × 10⁻²⁴ grams

Therefore;

18.0042 amu = 18.0042 ×  1.66 × 10⁻²⁴ grams ≈ 2.99×10⁻²³ grams

The calculated mass of one atom of oxygen-18 ≈ 2.99×10⁻²³ grams

The atomic mass unit can be taken as the mass in grams of one mole of the substance

Therefore, the mass of one mole of the oxygen 18 atom = 18.0042 g

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.