Surface over which the air mass was formed.
Answer:
Explanation: Carbon and silicon BOTH come from Group 14 of the Periodic Table , i.e. both formally have the same number of valence electrons, 4 such electrons.........
One mole of NaCl weighs 58.44 grams
Therefore 1L of one mole of NaCl contains 58.44 grams
1L of 0.2m NaCl contains 58.44x0.2 = 11.69grams
300mL of 0.2m NaCl contains 11.69x0.3 = 3.51 grams
One oxygen atom shares two electron with two hydrogen atoms in this way water molecules are formed. The bond between oxygen and hydrogen is covalent bond.
<h3>What is covalent bond ?</h3>
An electron exchange that results in the formation of electron pairs between atoms is known as a covalent bond. Bonding pairs or sharing pairs are the names given to these electron pairs.
Covalent bonding is the stable equilibrium of the attractive and repulsive forces between atoms when they share electrons.
According to the amount of shared electron pairs, there are three different forms of covalent bonds. single covalent bond is one type of covalent bond. covalent double bond and covalent triple bond.
Thus, option B is correct .
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Answer:
ΔH° = + 6.2 kJ
Explanation:
Fe₂O₃(s) + 3CO(g) –––––> 2 Fe(s) + 3 CO₂(g); ΔH° = –26.8 kJ ......... ( 1 )
FeO(s) + CO(g) –––––> Fe(s) + CO₂(g); ΔH° = –16.5 kJ .........( 2 )
Multiplying equation ( 2 ) by 2 and subtracting it from ( 1 )
Fe₂O₃(s) + 3CO(g) -2 FeO(s) - 2CO(g) ––> 2 Fe(s) + 3 CO₂(g) - 2Fe(s) - 2CO₂(g) ΔH° = –26.8 kJ - ( 2 x –16.5 kJ )
Fe₂O₃(s) + CO(g) -2 FeO(s)––> CO₂(g) ΔH° = –26.8 kJ + 33 kJ
Fe₂O₃(s) + CO(g) ––>2 FeO(s) +CO₂(g) ΔH° = + 6.2 kJ
Required ΔH° = + 6.2 kJ Ans .
