The formula for determination of atomic mass given the mass of isotopes and relative abundance is:
Ar = ∑(mass * abundance) / 100
Ar = (68.92558 * 60.108 + 70.92470 * 39.892) / 100
Ar = 69.72306
The atomic mass of gallium is 69.72306 amu
Answer:
Exolaiend in explanation section
Explanation:
First of all, the automatic hammer is used to drive nails into tight spaces where where we can't get a sufficient striking force if we are to use a normal regular hammer in driving the nail.
So the nail to be driven is lifted out of rest(it's position). The energy here is gravitational potential energy.
Now, when it is driven into the tight spaces, the gravitational energy would be converted to kinetic energy due to the motion and speed involved.
Answer:
-800 kJ/mol
Explanation:
To solve the problem, we have to express the enthalpy of combustion (ΔHc) in kJ per mole (kJ/mol).
First, we have to calculate the moles of methane (CH₄) there are in 2.50 g of substance. For this, we divide the mass into the molecular weight Mw) of CH₄:
Mw(CH₄) = 12 g/mol C + (1 g/mol H x 4) = 16 g/mol
moles CH₄ = mass CH₄/Mw(CH₄)= 2.50 g/(16 g/mol) = 0.15625 mol CH₄
Now, we divide the heat released into the moles of CH₄ to obtain the enthalpy per mole of CH₄:
ΔHc = heat/mol CH₄ = 125 kJ/(0.15625 mol) = 800 kJ/mol
Therefore, the enthalpy of combustion of methane is -800 kJ/mol (the minus sign indicated that the heat is released).
<span>It is used for the separation of fluids, gas or liquid, based on density.
Hope this helps!</span>
Density = mass / volume
Density = 7.5 g / 5.0 cm3
Density = 1.5 g/cm3
