Answer:
248 miles
Explanation:
At an average altitude of 248 miles (400 kilometers) above Earth, the space station is the third brightest object in the sky.
Answer:
Isotopes have same atomic numbers, no. of protons and no. of electrons. Only their no. of neutrons and atomic mass are changed.
<u>Na - 24:</u>
Atomic Mass = 24
Atomic No. = 11
Hence,
No. of protons in Na-24 = 11
No. of neutrons = Atomic Mass - Atomic Number
No. of neutrons = 24 - 11
No. of neutrons = 13
Atomic Number = 11
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Hope this helped!
<h3>~AH1807</h3><h3>Peace!</h3>
The service rating of passengers car and commercial automotive motor oils
Answer:
90.3 kJ/mol
Explanation:
Let's consider the following thermochemical equation.
2 NO(g) + O₂(g) → 2 NO₂(g) ∆H°rxn = –114.2 kJ
We can find the standard enthalpy of formation for NO using the following expression.
∆H°rxn = 2 mol × ΔH°f(NO₂(g)) - 2 mol × ΔH°f(NO(g)) - 1 mol × ΔH°f(O₂(g))
∆H°rxn = 2 mol × ΔH°f(NO₂(g)) - 2 mol × ΔH°f(NO(g)) - 1 mol × 0 kJ/mol
∆H°rxn = 2 mol × ΔH°f(NO₂(g)) - 2 mol × ΔH°f(NO(g))
ΔH°f(NO(g)) = (2 mol × ΔH°f(NO₂(g)) - ∆H°rxn) / 2 mol
ΔH°f(NO(g)) = (2 mol × 33.2 kJ/mol + 114.2 kJ) / 2 mol
ΔH°f(NO(g)) = 90.3 kJ/mol
