Answer:
spandex and cotton is a natural mix for sporta clothing and undergarments to improve stretching properties and prevent odour
Answer:
3 NaOH (aq) + H3PO4 (aq) → Na3PO4 (aq) + 3 H2O (l)
Explanation:
This is an acid-base reaction (neutralization): NaOH is a base, H3PO4 is an acid.
Need more details of the question. What was in part a?
Answer:
55.5g of N₂
Explanation:
It is possible to find ΔH of a reaction by the sum of half-reaction (Hess's law), thus:
<em>(1) </em>4 NH₃ + 3 O₂ → 2 N₂ + 6 H₂O ΔH= -1556KJ
<em>(2) </em>N₂O + H₂ → N₂ + H₂O ΔH= -389.4 KJ
<em>(3) </em>H₂+ ½ O₂ → H₂O ΔH= -223.9 KJ
(4) = 1/2 (1) + 3 (2):
<em>(4) </em>2 NH₃ + 3 N₂O +3 H₂ + ³/₂ O₂ → 4 N₂ + 6 H₂O
ΔH = 1/2 (-1556kJ) + 3 (-389.4kJ) = -1946.2kJ
(4) - 3(3):
2 NH₃ + 3 N₂O → 4 N₂ + 3 H₂O ΔH = -1946.2kJ - 3 (-223.9 KJ)
ΔH = -1274.5 kJ
As when 5 moles of nitrogen are produced there are released 1274.5kJ, when are released 505kJ:
505kJ × (5 moles N₂ / 1274.5kJ) =<em> 1.98 moles of N₂. </em>In mass:
1.98moles N₂ ₓ (28g / 1mol) = <em>55.5g of N₂</em>
The correct option is C.
An atom can be either in the ground state or in an excited state. An atom is said to be in the ground state, if the total energy of its electron can not be lowered by moving one or more electrons into different orbitals. At the ground state, the electrons in the atom have the lowest energy possible and they are stable. On the other hand, an atom is said to be in an excited state, if the energy of its electrons can be lowered by transferring one or more electrons into different orbitals. An atom in an excited state has more energy and is less stable.