Answer:
A
Explanation:
Lanthanides share the following common properties: Silvery-white metals that tarnish when exposed to air, forming their oxides. Relatively soft metals. Hardness increases somewhat with higher atomic number.
Based on the data provided;
- number of moles of helium gas is 1.25 moles
- pressure at peak temperature is 259.3 kPa
- internal pressure is above 256 kPa, therefore, the balloon will burst.
- pressure should be reduced to a value less than 256 kPa by reducing the temperature
<h3>What is the ideal has equation?</h3>
The ideal gas equation relatesthe pressure, volume, moles and temperature of a gas.
The moles of helium gas is calculated using the Ideal gas equation:
n is the number of moles of gas
R is molar gas constant = 8.314 L⋅kPa/Kmol
P is pressure = 239 kPa
T is temperature = 21°C = 294 K
V is volume = 12.8 L
Therefore;
n = PV/RT
n = 239 × 12.8 / 8.314 × 294
n = 1.25 moles
The number of moles of helium gas is 1.25 moles
At peak temperature, T = 46°C = 319 K
Using P1/T1 = P2/T2
P2 = P1T2/T1
P2 = 239 × 319/294
P2 = 259.3 kPa
The pressure at peak temperature is 259.3 kPa
At 42°C, T = 315 K
Using P1/T1 = P2/T2
P2 = P1T2/T1
P2 = 239 × 315/294
P2 = 256.07 kPa
Since the internal pressure is above 256 kPa, the balloon will burst.
The pressure should be reduced to a value less than 256 kPa by reducing the temperature.
Learn more about gas ideal gas equation at: brainly.com/question/12873752
Answer:
7.5 moles
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
3Cu + 2H3PO4 —> Cu3(PO4)2 + 3H2
From the balanced equation above,
3 moles of Cu reacted with 2 moles of H3PO4.
Therefore, Xmol of Cu will react with 5 moles of H3PO4 i.e
Xmol of Cu = (3 x 5)/2
Xmol of Cu = 7.5 moles
Therefore, 7.5 moles of Cu are needed to react with 5 moles of H3PO4.
Answer is: mass of salt is 311,15 g.
V(H₂O) = 1,48 l · 1000 ml/l = 1480 ml.
m(H₂O) = 1480 g = 1,48 kg.
d(solution) = 1,00 g/ml.
ΔT(solution) = 13,4°C = 13,4 K.
Kf = 1,86 K·kg/mol; cryoscopic constant of water
i(NaCl) = 2; Van 't Hoff factor.
ΔT(solution) = Kf · b · i.
b(NaCl) = 13,4 K ÷ (1,86 K·kg/mol · 2).
b(NaCl) = 3,6 mol/kg.
n(NaCl) = 3,6 mol · 1,48 kg= 5,328 mol.
m(NaCl) = 5,328 mol · 58,4 g/mol = 311,15 g.
