Answer:
Number of moles of hydrogen are 0.022 mol.
Explanation:
Given data:
Volume of hydrogen = 546 mL
Temperature = 30°C
Pressure = 100.45 kpa
Number of moles of hydrogen = ?
Solution:
According to ideal gas equation,
PV = nRT
P = pressure
V = volume
n = number of moles
R = ideal gas constant
T = temperature
First of all we will convert the units,
Temperature = 30 + 273 = 303 K
Pressure = 100.45 /101 = 0.99 atm
Volume of hydrogen = 546 mL× 1L /1000 mL =0.546 L
Now we will put the values in formula,
PV = nRT
n = PV/RT
n = 0.99 atm × 0.546 L /0.0821 atm.L/mol.K × 303 K
n = 0.541 atm. L / 24.876 atm.L / mol
n = 0.022 mol
First solve the moles of oxgen present in the compound
mol O = 6.93 g O ( 1 mol O / 16 g O )
mol O = 0.43 mol H
then solve the moles of hydrogen present
mol H = ( 7.36 - 6.93) g H ( 1 mol H / 1 g H)
mol H = 0.43 mol H
so the O and H are in the same mole content so the molecular formula would be OH, but the molar mass will not satisfy. so the answer would be
H2O2
Based on the diagram shown in the attached file
R = Radius of the sphere
a = Lattice constant
Using pythagoras theorem for the right angled triangle in figure 2
(4R)^2 = a^2 + a^2
16(R^2) = 2(a)^2
Solving the above equation
a=2R√2
To prove that the Atomic Packing factor is 0.74
Let the volume of atom in a unit cell be Vs
Total unit cell volume, Vc
Vc = a^3
Vc =(2R√2)^3
Vc=16R^3 √2 =22.63R^3
Since there are 4 atoms in the FCC unit cell
Vs=4*(4/3 πR^3)
Vs=5.33 πR^3
APF=(5.33 πR^3)/(22.63R^3 )
APF=0.74
Answer:
313.5cm²
Explanation:
Given parameters:
Weight of model = 105pounds
Pressure applied on the scale by model = 2.16pounds per square inch
Unknown:
Area of her feet in cm² = ?
Solution:
Pressure is the force per unit area;
Pressure =
Input the parameters and solve;
2.16 =
105 = 2.16 x Area
Area = = 48.6in²
We need now to convert the in² to cm²
1in² = 6.45cm²
48.6in² = 48.6 x 6.45 = 313.5cm²