Answer:
The correct option is;
B. -112 kJ
Explanation:
The parameters given are;
N (g) + O₂ (g) → NO (g) ΔH = 90 kJ/mol
N (g) + O₂ (g) → NO₂ (g) ΔH = 34 kJ/mol
The required chemical reaction is given as follows;
2NO (g) + O₂ (g) → 2NO₂ (g)
Therefore, the heat of formation of 2 moles of NO = 2 × 90 = 180 kJ
The heat of formation of 2 moles of NO₂ = 2 × 34 = 68 kJ
Hence, given that the heat of formation of O₂ at room temperature = 0 kJ/mol, we have;
Change in enthalpy of the chemical reaction = Heat of formation of the products - Heat of formation of the reactants
Change in enthalpy of the chemical reaction = 68 kJ - 180 kJ = -112 kJ
Change in enthalpy of the chemical reaction = -112 kJ.
Answer:
The molar mass of a substance is defined as the mass in grams of 1 mole of that substance. One mole of isotopically pure carbon-12 has a mass of 12 g. ... That is, the molar mass of a substance is the mass (in grams per mole) of 6.022 × 1023 atoms, molecules, or formula units of that substance.
Explanation:
Answer:
Explanation:
To calculate the moles, we use the equation:
According to stoichiometry :
2 moles of releases = 6542 kJ of heat
0.9858 moles of release = of heat
Thus heat given off by burning 7.700 g of will be absorbed by water.
Q = Heat absorbed= 3224kJ = 3224000J (1kJ=1000J)
m= mass of water = 5691 g
c = specific heat capacity =
Initial temperature of the water = = 21.0°C
Final temperature of the water = = ?
Putting in the values, we get:
The final temperature of the water is
Answer:
Decreases
Explanation:
Fatty acid which have the double bond or triple bond are called unsaturated fatty acids. Because of the double or triple bond, unsaturated fatty acids are loosely packed and form some distance among molecules which lowers the melting point of unsaturated fatty acids.
So, if the unsaturation of fatty acid will increase, it leads to more branched and loosely packed molecules and decreases the melting temperature accordingly.
Answer:
20
Explanation:
The atomic number tells you the amount of electrons and protons in an atom so if you add all of the electrons up (2+8+8+2) you get 20.