Here's my best guess
the volume of the unit cell is (385*10^-12)^3=5.7066*10^-29 m^3
multiply by density to get mass
mass = (7 g/cm^3)*(100^3 cm^3 / 1^3 m^3) * 5.7066*10^-29 m^3= 3.99466*10^-22 g
covert to moles
3.99466*10^-22 g * 1 mol / 239.82 g = 1.6657 *10^-24 mol
convert to number of units
1.6657 *10^-24 mol * 6.23*10^23 units/mol = 1.04
385 pm = 3.85*10^(-8) cm
The volume of the unit cell is the cube of that, which is 5.71*10^(-23) cm^3. Since the ratio of mass to volume (i.e. the density) must be the same no matter what amount of TlCl you have, you can say:
7 = x/(5.71*10^(-23)), where x is the mass of the unit cell. Solving for x, you get 4*10^(-22) g.
The mass of a molecule of TlCl is 240 amu, which in grams is 4*10^(-22) g. The mass of the unit cell and the mass of a molecule of TlCl is the same. Therefore there is one formula unit of TlCl per unit cell.
Answer:
Heat energy required (Q) = 10.736 KJ
Explanation:
Given:
Specific heat of ethanol (C) = 2.44 J/g °C
Mass of ethanol (M) = 50 gram
Initial temperature (T1) = -20°C
Final temperature (T1) = 68°C
Find:
Heat energy required (Q) = ?
Computation:
Change in temperature (ΔT) = 68°C - (-20°C)
Change in temperature (ΔT) = 88°C
Heat energy required (Q) = mC(ΔT)
Heat energy required (Q) = (50)(2.44)(88)
Heat energy required (Q) = 10,736 J
Heat energy required (Q) = 10.736 KJ
The number of particles in one mole is given be Avagadro's number <span>6.022×10^23
Multiply by number of moles.
3 ×10^-21 mol * 6.022 ×10^23 molecules/mol = </span><span>1,807 molecules
(rounded to nearest whole number)
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Answer: I think you did nothing wrong
Explanation: I think you did nothing wrong