When a gas is pumped into a small rigid container the pressure inside the container increases as more particles are added. If th
2 answers:
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Answer:
The value becomes 0.0821 L-atm/K⁻¹-mol⁻¹.
Explanation:
The value of gas constant is 0.0821.
We know that, the ideal gas law is as follows :
Where
P is pressure
V is volume
T is temperature
In order to use the Ideal Gas Constant of 0.0821, the units are follows :
Volume = Litre (L)
Pressure = atm
Amount = mol⁻¹
Temperature = K⁻¹
So, the value becomes 0.0821 L-atm/K⁻¹-mol⁻¹.
Answer:
D
Explanation:
The problem says that carbon dioxide was collected at 740.4 mmHg, but this is a pressure that includes the pressure of the water. We want to only use the pressure of the carbon dioxide, so subtract the pressure of the water (21.0 mmHg) from 740.4 mmHg:
740.4 - 21.0 = 719.4 mmHg
Now, we can use the ideal gas law to find the number of moles of carbon dioxide we have: PV = nRT.
- the pressure P is 719.4 mmHg
- the volume V is 38.82 mL, but we need Litres, so divide 38.82 by 1000: 38.82 / 1000 = 0.03882 L
- the moles n is what we want to find
- the gas constant R is 62.36 L mmHg / (mol K)
- the temperature T is 23.0°C, but we need this in Kelvins, so add 273 to 23.0: 23.0 + 273 = 296 K
Plug all these in:
PV = nRT
(719.4 mmHg) * (0.03882 L) = n * (62.36) * (296 K)
n ≈ 0.00151 mol
Note that this is moles of carbon dioxide, but since we want CaCO3, we need to convert moles using the reaction. It's just a 1 to 1 ratio, so we still have 0.00151 moles of CaCO3. Now, convert moles to grams. The molar mass of CaCO3 is 40.08 + 12.01 + 3 * 16 = 100.09 g/mol.
To find the mass percent, divide 0.151 by the total mass of the tablet, which is 0.3211 g:
0.151 g / 0.3211 g = 0.471 = 47.1%
The answer is D.