Which equation represents a double replacement reaction? A) 2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g) B) 2Al(s) + 3Cl2(g) - 2AlCl3(s) C) 2AlCl3(s) + 2Al(s) + 3Cl2(g) D) AlCl3(aq) + 3KOH(aq) - Al(OH)3(s) + 3KCl(aq)​

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.

the enthalpy change that occurs in a system when matter is transformed by a given chemical reaction, when all reactants and products are in their standard states.

  the moles   of   sulfuric acid   that are needed to react   completely with 6.4   moles   of lithium hydroxide   is 12.8   moles ( answer a)

calculation

step 1 : write a balanced   chemical equation

2lioh   + h₂so₄   →   li₂so₄   +2h₂o

step 2 : use the mole ratio   to determine   the   moles h₂so₄

from   equation above   lioh: h₂so₄   is 2: 1 therefore   the moles of h₂so₄

= 6.4   x 2/1   = 12.8   moles   of h₂so₄