Answer:
20.2 kJ
Explanation:
Based on the information in the reaction, the amount of heat released per mole of Na₂O₂ (the molar enthalpy) is calculated as follows:
126 kJ / 2 mol = 63 kJ/mol Na₂O₂
The number of moles in 25.0g of Na₂O₂ must be calculated using the molecular weight of Na₂O₂ (77.978 g/mol):
(25.0 g)/(77.978 g/mol) = 0.32060 mol Na₂O₂
Thus, the heat released will be:
(63 kJ/mol)(0.32060 mol) = 20.2 kJ
Answer:
Si₁₄ = 1s² 2s² 2p⁶ 3s² 3p²
Explanation:
Silicon is present in group 14 of periodic table.
It is blue-gray color metalloid.
Its atomic mass is 28 g/mol.
It is mostly used to make allow.
The most important alloy are Al-Si and Fe-Si. These are used to make different machine tools, transformer plates, engine etc.
Its atomic number is 14 and electronic configuration can be written as,
Electronic configuration:
Si₁₄ = 1s² 2s² 2p⁶ 3s² 3p²
The noble gas electronic configuration or abbreviated electronic configuration can also be written.
Si₁₄ = [Ne] 3s² 3p²
The atomic number of neon is 10. Its electronic configuration is,
Ne₁₀ = 1s² 2s² 2p⁶
That's why we write [Ne] for 1s² 2s² 2p⁶ in abbreviated electronic configuration of Si.
Answer:
(a) The mass of an object remains the same always. It is independent of its location. In this case, an iron nail is ground into powder.
Explanation:
please mark this answer as brainliest
Answer:
Explanation:
Double Bond => An Alkene molecule
So, the suffix will be "-ene"
7 Carbons => So, we'll use the prefix "Hept-"
Combining the suffix and prefix, we get:
=> Heptene
Answer: B: Iron rusts when exposed to air.
Explanation:
