Answer:
The flask has to be closed during the hydrochloric acid and sodium carbonate reaction as the resultant gas got trapped inside the closed flask.
Explanation:
The hydrochloric acid and sodium carbonate reaction was exothermic that caused the pressure to decrease. The flask has to be closed during the hydrochloric acid and sodium carbonate reaction as the resultant gas got trapped inside the closed flask.
In exothermic reactions, energy is produced in the form of heat or light.
Answer:
8.8g of Al are necessaries
Explanation:
Based on the reaction, 2 moles of Al are required to produce 3 moles of hydrogen gas.
To solve this question we must find the moles of H2 in 11L at STP using PV = nRT. With these moles we can find the moles of Al required and its mass as follows:
<em>Moles H2:</em>
PV = nRT; PV/RT = n
<em>Where P is pressure = 1atm at STP; V is volume = 11L; R is gas constant = 0.082atmL/molK and T is absolute temperature = 273.15K at STP</em>
Replacing:
1atm*11L/0.082atmL/molK*273.15K = n
n = 0.491 moles of H2 must be produced
<em />
<em>Moles Al:</em>
0.491 moles of H2 * (2mol Al / 3mol H2) = 0.327moles of Al are required
<em />
<em>Mass Al -Molar mass: 26.98g/mol-:</em>
0.327moles of Al * (26.98g / mol) = 8.8g of Al are necessaries
Because as the air hits the charcoal it becomes ash and changes color.
The total kinetic energy of the gas sample is 3.3 KJ
<h3>What is kinetic energy? </h3>
This is the energy possessed by an object in motion. Mathematically, it can be expressed as:
KE = ½mv²
Where
- KE is the kinetic energy
- m is the mass
- v is the velocity
<h3>How to determine the mass of the fluorine gas</h3>
- Molar mass of fluorine gas = 38 g/mol
- Mole of fluorine gas = 1 mole
- Mass of fluorine gas = ?
Mass = mole × molar mass
Mass of fluorine gas = 1 × 38
Mass of fluorine gas = 38 g
<h3>How to determine the KE of the gas sample</h3>
- Mass (m) = 38 g = 38 / 1000 = 0.038 Kg
- Velocity (v) = 415 m/s
- Kinetic energy (KE) =?
KE = ½mv²
KE = ½ × 0.038 × 415²
KE = 3272.275 J
Divide by 1000 to express in kilojoule
KE = 3272.275 / 1000
KE = 3.3 KJ
Learn more about energy:
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