The person who is behind the boat will see much powerful and bigger waves than the person who is in front of the boat. This phenomenon is caused by the Doppler effect which describes the changes in the observed frequency of a wave whenever there is relative motion between the wave source and the observer.
The percentage of hydrogen in C7H18 is calculated as follows:
[18/(12*7+1*8)]*100=18%
The amount of hydrogen in 5.2moles is given by:(18/100)*5.2=0.94moles
Electrons are both gained and lost.
Balanced equation: 2Al+Fe2O3–> Al2O3+2Fe
Using mole calculations you can find that 10g of Al produces 24.3g of Fe under the conditions described