The first one is exothermic because energy is a reactant, the second formula is endothermic
sorry about the late response...
<u>If an earthworm is exposed to dry conditions, then it will retreat to a moist place because its skin needs to stay moist for the earthworm to survive.</u>
Answer:
12.32 L.
Explanation:
The following data were obtained from the question:
Mass of CH4 = 8.80 g
Volume of CH4 =?
Next, we shall determine the number of mole in 8.80 g of CH4. This can be obtained as follow:
Mass of CH4 = 8.80 g
Molar mass of CH4 = 12 + (1×4) = 12 + 4 = 16 g/mol
Mole of CH4 =?
Mole = mass/Molar mass
Mole of CH4 = 8.80 / 16
Mole of CH4 = 0.55 mole.
Finally, we shall determine the volume of the gas at stp as illustrated below:
1 mole of a gas occupies 22.4 L at stp.
Therefore, 0.55 mole of CH4 will occupy = 0.55 × 22.4 = 12.32 L.
Thus, 8.80 g of CH4 occupies 12.32 L at STP.
Explanation:
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Answer:
-1.94 * 10^-18 J
Since the electron moved from a higher to a lower energy level (n = 3 → n = 1) it is an emission.
Explanation:
From Rydberg equation;
E = -RH(1/n^2final - 1/n^2initial)
For a transition from n = 3 → n = 1
RH = 2.18 * 10^-18 J
E = -(2.18 * 10^-18) (1/1^2 - (1/3^2)
E = -(2.18 * 10^-18) (1-1/9)
E= -(2.18 * 10^-18) (8/9)
E = -1.94 * 10^-18 J
