A student did an experiment to determine the specific heat capacity of a metal alloy. The student put a sample of the alloy in b
oiling water for several minutes, then quickly transferred the alloy into a calorimeter containing water originally at 25°C. The temperature of the water was monitored over time. The data are given in the graph above.
(a) What is the value of ΔT that the student should use to calculate the value of q, the heat gained by the water?
(b) In terms of what occurs at the particulate level, explain how the temperature of the water increases after the alloy sample is added.
(c) The student claims that thermal equilibrium is reached at time t. Justify the student’s claim. In your justification, include a description of what occurs at the particulate level when the alloy and the water have reached thermal equilibrium.
(a) What is the value of ΔT that the student should use to calculate the value of q, the heat gained by the water?
(b) In terms of what occurs at the particulate level, explain how the temperature of the water increases after the alloy sample is added.
(c) The student claims that thermal equilibrium is reached at time t. Justify the student’s claim. In your justification, include a description of what occurs at the particulate level when the alloy and the water have reached thermal equilibrium.
1 answer:
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<u>Answer:</u> The number of moles of gas present is 0.276 moles
<u>Explanation:</u>
To calculate the number of moles of gas, we use the equation given by ideal gas:
PV = nRT
where,
P = Pressure of the gas = 725 mm Hg
V = Volume of the gas = 7.55 L
n = number of moles of gas = ?
R = Gas constant =
T = Temperature of the gas =
Putting values in above equation, we get:
Hence, the number of moles of gas present is 0.276 moles
The daughter isotope (a decay product)of O-15 = N-15(Nitrogen 15)
<h3>Further explanation </h3>Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,
- alpha α particles ₂He⁴
- beta β ₋₁e⁰ particles
- gamma particles γ
- positron particles ₁e⁰
O-15 emits positron particles ₁e⁰, so the atomic number decreases by 1, the mass number is the same
Reaction
The mass number of the daughter isotope = 15, atomic number = 7
If we look at the periodic system, the element with atomic number 7 is Nitrogen (N)