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# Calculate the force of gravity on earth of an object that has a mass of 200 kg. (answer)

Hello Amber, In a nutshell, Newton's second law states that force is equal to mass*acceleration, F=ma.  The SI unit of mass is the kilogram (kg), and the SI units of acceleration are meter/second squared  (m/s^2).  If we multiply kg (m/s^2), we get kg m/s^2 which equals the...

# Calculate concentrations in air, water and octanol (answer)

Helllo Brook, I expect that "logKOW" means the log of the octanol-water partition coefficient.  Taking the inverse log of 3.12, we get 1318.256739.  If before the extraction we have 0.10g of o-xylene in water, then post extraction we have x grams of o-xylene in octanol, and...

# At 1 atm, how much energy is required to heat 77.0 g of H2O(s) at –12.0 °C to H2O(g) at 121.0 °C? (answer)

Hello Kaya,   Using your numbers for the specific heats of solid, liquid, and gaseous water and the enthalpies of fusion and vaporization, I get 236.8 kJ of energy.   Starting at -12.0 degrees C, q1=m CP dt=77.0g(2.087 J/g*C)(0+12.0 C)=1.93 kJ q2=dH of fusion=6010...