6 4 marks Calculate 4 for the following reaction Note sig fi

6) (4 marks) Calculate 4\" for the following reaction: (Note: sig figs will be evaluated.) SiBrd/) + 4H Br(g)-. Silla(g) + 4Br2(l), Use the following reactions and given H\'s Si(s) +2Br2(1)-SiBra( 2HBr(g) H2(g) +(Brall SiH4(g) Si(s) + 2H2(g) HP=-193 kJ/mol HP= 146.8 kJ/mol aho = 87.4 k/mol (2 marks) Arrange the following compounds in order of increasing lattice energy Al2Se3, MgSe, K2S incr as marks) Using the following information, calculate the first ionization energy (En) for sodium. Be sure to write the equation for this process. Show your work for part Br(g) e- Br\"(g) + EEA=-330.9 kJ/mol Na(s) + ½Br2(l) NaBr(s) Hform --360.0 kJ/mol Br2(g) Na+(g) Na(s) 2Br(g) + Br(g) Na(g) BDE NaBr(s) H.ubl= 192.0 kJ/mol = · U --743.3kl/mol 107.3k/mol ·

Solution

6)

Reverse the equation 1 and 3 and multiply the Equation second with 2.

We get

SiBr4 -----> Si + 2Br2................ H1 = 193 kJmol-1

Si + 2H2 - - - - - > SiH4 ... ....... H2 = - 87.4 kJmol-1

4HBr - - - - - > 2 H2 + 2Br2 ........ H3 = 293.6kJmol-1

Add the three equation we get :

SiBr4 + 4HBr - - - - - - - > SiH4 + 4Br2

So,

Hrxn =   H1 +   H2 + H3

= ( 193 - 87.4 + 293.6) kJmol-1

=399.2 kJmol-1