The answer is 
6.8 * 10^-15
The explanation:
1- we have to convert all measurements to the same units:  
Conversions:  
when 1 m = 100 cm  
and 1 m = 10^12 pm  
So,
proton radius: 1.0*10^-13 cm * (1m / 100 cm) = 10^-15 m  
proton volume: 4/3 * pi * r^3 = 4/3 * pi * (10^-15 m)^3 = 4.2 * 10^-45 cu. meters  
and
H atom radius: 52.9 pm * (1m / 10^12 pm) = 5.29 * 10^-11 m  
H atom volume: 4/3 * pi * r^3 = 4/3 * pi * (5.29 * 10^-11 m)^3 = 6.2 × 10^-31 cu. meters  
So,
2- Fraction of space occupied by nucleus = proton volume / H atom volume  
= (4.2 * 10^-45 cu. meters) / (6.2 × 10^-31 cu. meters)  
= 6.8 * 10^-15  
So, the "fraction" would be 6.8 * 10^-15 out of 1.
 
        
                    
             
        
        
        
Mass/volume = density
mass = (440 mg)*(1g)/(1000mg) = 0.440g
volume = (1000cm)(1000cm)(t)
 where t = thickness
density = 2.70 g/cm^3 = (0.440g)/((1000cm)(1000cm)(t))
multiply both sides by 't' and divide both sides by (2.70g/cm^3)
t = (0.440) / ((1000cm)(1000cm)(2.70)) = 1.629x10^-7 cm
t = (1.629 x 10^-7 cm)*(1000000 micrometers)/(1 cm) = 0.1629 micrometers
Answer is t = 0.1629 micrometers
        
             
        
        
        
Answer:
Volume of dry gas at STP = 0.432 liters or 432 ml
Explanation:
Given:
Pressure (P) = 740 mmHg - 24 mmHg = 716 mmHg
Temperature (t) = 25 degrees C + 273 K = 298 K
500 ml = 0.5 l
Find:
Volume of dry gas at STP
Computation:
[P1][V1] / T1 = [P2][V2] / T2
[716][0.5] / 298 K = [760][ x Liters] / 273 K
x = 0.432 Liters 
Volume of dry gas at STP = 0.432 liters or 432 ml
 
        
             
        
        
        
Answer:
Buy local and eat a more diversified diet including less meat and dairy to reduce your carbon emissions resulting from the use of fossil fuel-based fertilizers, pesticides, and gas required to produce and transport of the food you eat. Support clean energy sources.
Explanation:  or
Alternatives to drivingWhen possible, walk or ride your bike in order to avoid carbon emissions completely. Carpooling and public transportation drastically reduce CO2 emissions by spreading them out over many riders.
 
        
             
        
        
        
Answer:
a) Measurements have a good precision.
Explanation:
Accuracy is the proximity of the data to the value considered as real, in this situation we do not know the real value and we do not know if the data is accurate or not, so we can discard options b and d.
Now, precision is the proximity of the data obtained among themselves and that is what we can observe, so the appropriate answer is the option a.