Determine the number of particles in 0.332 g of NaCl (molar mass NaCl=58.44 g/mol).

3.42×10²¹ of particles

Explanation:

To determine the number of particles we should know, that:

1 mol of anything contains 6.02×10²³ particles

Therefore we have to find out, how many moles corresponds to 0.332 g of NaCl.

The conversion is: 0.332 g / 58.44 g/mol = 0.00568 moles

The rule of three to determine the number of particles is:

1 mol of NaCl has 6.02×10²³ particles

0.00568 moles must have (0.00568 . 6.02×10²³ particles )/1 = 3.42×10²¹

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.