In the early days of automobiles, illumination at night was provided by burning acetylene, c2h2. though no longer used as auto headlamps, acetylene is still used as a source of light by some cave explorers. the acetylene is (was) prepared in the lamp by the reaction of water with calcium carbide, cac2: cac2(s)+2h2o(l)⟶ca(oh)2(s)+c2h2(g). calculate the standard enthalpy of the reaction. the δh∘f of cac2 is −15.14 kcal/mol.

11 players on a field that has a maximum of 11 players

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.

answer; 4 electrons;