by making sure they are in the lowest ratio. by adding them to see if they total 100. by checking that they are whole-number multiples. by dividing them by the molar mass.
Answer:
The answer to your question is Gallium-71 = 70.9202 amu
Explanation:
Gallium atomic weight = 69.7
Gallium-69 = 68.9 amu abundance = 60.4%
Gallium-71 = x abundance = 39.6%
To solve this problem just write an equation and solve it for the mass of gallium-71.
Equation
Gallium = Gallium-69(abundance) + Gallium-71(abundance)
Substitution
69.7 = (68.9)(0.604) + Gallium-71(0.396)
69.7 = 41.6156 + Gallium-71(0.396)
Gallium-71(0.396) = 69.7 - 41.6156
Gallium-71(0.396) = 28.0844
Gallium-71 = 28.0844/0.396
Gallium-71 = 70.9202 amu
The reaction equation is:
Li + Br → LiBr
39 grams of Li = 39 / 7 = 5.57 moles of lithium
41.5 grams of Br = 41.5 / 80 = 0.52 mole of bromine
There is enough wind power in the U.S. to drive the entire country, but aesthetic considerations cause some people to oppose its use.
Answer:
q = 40.57 kJ; w = -3.10 kJ; strong H-bonds must be broken.
Explanation:
1. Heat absorbed
q = nΔH = 1 mol × (40.57 kJ/1 mol) = 40.57 kJ
2. Change in volume
V(water) = 0.018 L
pV = nRT
1 atm × V = 1 mol × 0.082 06 L·atm·K⁻¹mol⁻¹ × 373.15 K
V = 30.62 L
ΔV = V(steam) - V(water) = 30.62 L - 0.018 L = 30.60 L
3. Work done
w = -pΔV = - 1 atm × 30.60 L = -30.60 L·atm
w = -30.60 L·atm × (101.325 J/1 L·atm) = -3100 J = -3.10 kJ
4. Why the difference?
Every gas does 3.10 kJ of work when it expands at 100 °C and 1 atm.
The difference is in the heat of vaporization. Water molecules are strongly hydrogen bonded to each other, so it takes a large amount of energy to convert water from the liquid phase to the vapour phase.
