Thermal decomposition of Sodium Hydrogen Carbonate (NaHCO3)

Here are the solutions to your chemistry questions: 20. Thermal decomposition of Sodium Hydrogen Carbonate (NaHCO_3) a) Sodium Hydrogen Carbonate (NaHCO_3) is an ionic compound composed of a sodium ion and a hydrogen carbonate ion. The two radicals (polyatomic ions) present or closely related in this context are: 1. Hydrogen Carbonate radical (also known as Bicarbonate radical): HCO_3^- 2. Carbonate radical: CO_3^2- (This radical is formed during the decomposition of sodium hydrogen carbonate). b) The thermal decomposition of Sodium Hydrogen Carbonate produces Sodium Carbonate, Water, and Carbon (IV) oxide. Step 1: Write the unbalanced chemical equation with state symbols. NaHCO_3(s) Na_2CO_3(s) + H_2O(g) + CO_2(g) Step 2: Balance the sodium atoms. There is 1 Na on the left and 2 Na on the right. Place a coefficient of 2 in front of NaHCO_3. 2NaHCO_3(s) Na_2CO_3(s) + H_2O(g) + CO_2(g) Step 3: Verify the balance of all other atoms: Sodium (Na): Left = 2 × 1 = 2, Right = 1 × 2 = 2 (Balanced) Hydrogen (H): Left = 2 × 1 = 2, Right = 1 × 2 = 2 (Balanced) Carbon (C): Left = 2 × 1 = 2, Right = 1 × 1 (in Na_2CO_3) + 1 × 1 (in CO_2) = 2 (Balanced) Oxygen (O): Left = 2 × 3 = 6, Right = 1 × 3 (in Na_2CO_3) + 1 × 1 (in H_2O) + 1 × 2 (in CO_2) = 3 + 1 + 2 = 6 (Balanced) The balanced chemical equation for this thermal decomposition is: 2NaHCO_3(s) → Na_2CO_3(s) + H_2O(g) + CO_2(g) 21. Doping Silicon a) Silicon (Si) has an atomic number Z=14, meaning a neutral Silicon atom has 14 electrons. Step 1: Fill the atomic orbitals in order of increasing energy. 1s orbital: 2 electrons 2s orbital: 2 electrons 2p orbital: 6 electrons 3s orbital: 2 electrons 3p orbital: The remaining 14 - (2+2+6+2) = 2 electrons. The s, p configuration for a neutral Silicon atom is: 1s^2 2s^2 2p^6 3s^2 3p^2 b) The element used for doping has "exactly one more electron in its p-orbital than Silicon." Step 1: Silicon's outermost p-orbital configuration is 3p^2. Step 2: An element with one more electron in its p-orbital would have a 3p^3 configuration. This means it is in the same period (Period 3) but one group to the right of Silicon (Group 14). Step 3: The element in Period 3, Group 15 is Phosphorus (P). Step 4: Verify the electron configuration for Phosphorus (P, Z=15). 1s orbital: 2 electrons 2s orbital: 2 electrons 2p orbital: 6 electrons 3s orbital: 2 electrons 3p orbital: The remaining 15 - (2+2+6+2) = 3 electrons. The element used for doping is Phosphorus (P). Its s, p configuration is: 1s^2 2s^2 2p^6 3s^2 3p^3