Option C. A compound being separated into 2 elements represents a chemical change.
The new volume if the balloon is cooled at constant pressure is 3.98 L.
Charles's law, states that the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature if the pressure remains constant.
The new volume is calculated using the Charles law formula
V₁ / T₁ = V₂ / T₂
where,
V₁ = The initial volume of air = 4.24 l
T₁ = 23.00 °C into kelvin = 23 +273 =296 K
T₂ = 5.00 °C into kelvin = 5.00 + 273 = 278 K
V₂ = ?
By making V₂ subject the subject of the formula by multiplying both sides by T₂
V₂ = ( V₁ × T₂ ) / T₁
V₂ = (4.24 L × 278 K) / 296 k
= 3.98 L
Therefore, the new volume, if the balloon is cooled at constant pressure, is 3.98 L.
An air-filled balloon will contract when chilled and expand when heated. This occurs because the gas that makes up the air within the balloon expands when it is warm and contracts when it is cool.
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Answer:
C
Explanation:
∆H°f means the enthalpy change of formation of one mole of substance by its constituent elements under standard conditions.
So in an equation for ∆H°f, we must see 2 or more elements as reactants combining to form a compound.
In the 4 answers, only C represents elements forming a substance (Al(s) + 3/2O2(g) + 3/2H2(g) -> Al(OH)3(s)),
while the others include compounds as one of their reactants.
