Answer:
400 mL
Explanation:
Given data:
Mass of barium = 2.17 g
Pressure = 748 mmHg (748/760 = 0.98 atm)
Temperature = 21 °C ( 273+ 21 = 294k)
Milliliters of H₂ evolved = ?
Solution:
chemical equation:
Ba + 2H₂O → Ba(OH)₂ + H₂
Number of moles of barium:
Number of moles = mass/ molar mass
Number of moles = 2.17 g / 137.327 g/mol
Number of moles = 0.016 mol
Now we will compare the moles of barium with H₂.
Ba : H₂
1 : 1
0.016 : 0.016
Milliliters of H₂:
PV = nRT
V = nRT/P
V = 0.016 mol × 0.0821 atm. mol⁻¹.k⁻¹.L×294 k/0.98 atm
V = 0.39 atm. L/0.98 atm
V = 0.4 L
L to mL
0.4 × 1000 = 400 mL
Answer:
Explanation:
1)The charge of one electron is given by
1 e = - 1.6 * 10-19 C
Then – 1 C = 1 e / ( 1.6 * 10-19 )
= 6.25 * 1018 e
So one-coulomb charge has 6.25 * 1018 electrons
2)Let q1 and q2 be two charges separated by a distance r
Then q1 = - 40 µC = - 40 * 10-6 C
And q2 = 108 µC = 108 * 10-6 C
